Program with Abstracts, Volume 63, Number 4

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Vol. 63, No. 4 – Program with Abstracts

AEG2020

Virtual Conference

Program with Abstracts

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AEG 63rd Annual Meeting – Program with Abstracts

AEG News (ISSN 0899-5788; USPS 954-380) is published five times a year by the Association of Environmental & Engineering Geologists (AEG). This includes three regular issues published in Spring (#2), Summer (#3) and Winter (#5) and two special issues: the Annual Report and Directory (#1) in March and the Annual Meeting Program with Abstracts (#4) in September (digital publication only). Digital copies of the Program with Abstracts are distributed at the AEG Annual Meeting. Association members receive an electronic copy of all five issues of the AEG News as part of their dues. Print subscription for Association members, which includes all three regular issues of the AEG News, is $40 in addition to annual membership dues. Nonmember annual subscription is $50 and includes only the three regular issues; the Annual Report and Directory issue is priced separately. Back copies of AEG News regular issues are $12 each. Inquiries should be sent to AEG Headquarters: Association Manager, 3053 Nationwide Parkway, Brunswick, OH 44212 330-578-4900.

Periodical Postage paid at Brunswick, OH, and additional mailing offices: POSTMASTER: Send address changes to AEG News, 3053 Nationwide Parkway, Brunswick, OH 44212, USA. AEG News is printed by Allen Press, Lawrence, KS, 66044, USA. © 2020 Association of Environmental & Engineering Geologists—All Rights Reserved Views expressed in this publication are not necessarily those officially representing the Association of Environmental & Engineering Geologists except where expressly stated.

Acquisitions Editor: AEG News Co-Editors Visty P. Dalal Anna Saindon news@aegweb.org Geotechnology, Inc.

11816 Lackland Content Editor: Road, Suite 150 St. Louis, MO 63146 Bill Roman 314-581-6286 wroman@gfnet.com news@aegweb.org

Managing Editor/Production Andrea Leigh Ptak Communicating Words & Images 6542 52nd Ave. So. Seattle, WA 98118 206-300-2067 www.andrealeighptak.com andrealeighptak@me.com

Submission Information In order of preference:

Table of Contents Table of Contents Schedule of Events Technical Session Numbers and Names Planning Committee Special Thanks Welcome Letter AEG 2020 Awardees AEG Foundation 2020 Scholars Sponsors

4 5 6 6 7 8 10 12

2020 Technical Program The 2019–20 AEG/GSA Richard H. Jahns Distinguished Lecturer The 2020–21 AEG/GSA Richard H. Jahns Distinguished Lecturer Keynote Speaker Outstanding Environmental & Engineering Geologic Project

15 16 17 18

Technical Program Schedule Wednesday, September 16 Thursday, September 17 Friday, September 18 Poster Sessions

23 24 26 29

Meeting Abstracts

30

Author and Title Index

53

Index to Advertisers

29

“On the Cover” Key

29

The association

1. Send files via email, preferably as attachments, to both email addresses above. Optimum file format is MSWord. Users of other software programs should convert their file to ASCII or text only. Photos and other images, charts, graphs, etc.) should be sent as separate images but may be included in the Word.doc for placement purposes.

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3. The policy of AEG News editorial staff is to limit the credentials of an individual to two. No effort will be made by the AEG News editorial staff to determine if individuals whose credentials are missing from the submitted copy actually have academic or professional credentials, nor will the staff verify the existence or correctness of the credentials submitted.

2019–20 Officers

For detailed guidelines visit: https://aeg.memberclicks.net/assets/docs/aeg_news_style_guide_0713.pdf

Advertising in the News

Headquarters: Association Manager: SHERI MASKOW J&M Business Solutions 3053 Nationwide Parkway, Brunswick, OH 44212 330-578-4900, manager@aegweb.org

Contact AEG Headquarters at advertising@aegweb.org.

AEG Foundation—President: WILLIAM FLANIGAN, president@aegfoundation.org

Submission Deadlines

Communications Director: BILL ROMAN, wroman@gfnet.com

https://aeg.memberclicks.net/aeg-news

Canada Agreement number: PM40063731; Return Undeliverable Canadian Addresses to: Station A, PO Box 54; Windsor, ON N9A 6J5; Email: returnsil@imex.pb.com

September 2020

President: CYNTHIA PALOMARES Texas Engineering Extension Service, Texas A&M University, Caldwell, Texas, president@aegweb.org Vice President/President Elect: WILLIAM GODWIN Consulting Geologist, Carmel, California, VP@aegweb.org Treasurer: MADDIE GERMAN Geologist, Raleigh, North Carolina, treasurer@aegweb.org Secretary: NATHAN SARACENO Senior Geologist, DiGioia Gray and Associates, Monroeville, Pennsylvania, secretary@aegweb.org Past President: DAVID FENSTER Geologist (Retired), North Potomac, Maryland, PP@aegweb.org

Association Contacts

AEG News welcomes your feedback. Letters should be sent with the writer's name, address, and daytime phone number via e-mail to news@aegweb.org. Letters may be edited for length and clarity.

AEG Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

Schedule of Events (All Times Are Central Time Zone) EVENT

TIME

TUESDAY, SEPTEMBER 15 AEG Executive Council Meeting

9:00am–4:00pm

WEDNESDAY, SEPTEMBER 16 Opening Session – Sponsored by Gannett Fleming Opening Session Welcome (AEG President Cynthia Palomares)

9:00am–9:10am

2019/2020 AEG/GSA Richard H. Jahns Distinguished Lecturer: Scott Lindvall

9:15am–9:45am

2020/2021 AEG/GSA Richard H. Jahns Distinguished Lecturer: Cheryl Hapke

9:50am–10:20am

AEG Outstanding Environmental & Engineering Geologic Project Award: Route 30 Landslide Remediation

10:25am–11:10am

National Keynote

11:15am–12:00pm

Break

12:00pm–12:15pm

Student & Young Professional Event: Get a Job and Make It Your Own – Sponsored by University of Pennsylvania

12:15pm–1:15pm

Technical Session #1: Symposium: Engineering Geology for Tunnels and Underground Construction – Sponsored by PBS Portland

12:15pm–4:00pm

Technical Session #2: Environmental Symposium 2020: Radon Occurrence and Remediation – Sponsored by Bryan Environmental Consulting and Princeton Geoscience

12:15pm–4:10pm

Afternoon Break

2:00pm–2:15pm

Volunteer Recognition Happy Hour – Sponsored by John Williams

4:15pm–4:45pm

Student/Professional Networking Happy Hour – Sponsored by Gill Editing Online

4:45pm–5:45pm

Women in AEG/AWG Happy Hour – Sponsored by Steele & Associates

4:45pm–5:45pm

Student and Professional Poster Presentations – Sponsored by Mount Sopris Instruments

ALL DAY

THURSDAY, SEPTEMBER 17 Technical Session #3: NOA Symposium: Hindsight in 2020 and Lessons for the Future – Sponsored by Gill Editing Online

9:00am–12:00pm

Technical Session #4: Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part I – Sponsored by Pali Consulting

9:00am–12:00pm

Break

12:00pm–12:15pm

Technical Session #5: Dams and Levees Lessons Learned Symposium, Part I – Sponsored by Schnabel Engineering

12:15pm–4:15pm

Technical Session #6: Landslide Symposium: Seeking Stable Slopes in a Time of Rapid Change – Sponsored by Landslide Technology

12:15pm–4:35pm

Afternoon Break

2:00pm–2:15pm

Special Event: Wine Happy Hour with Scott Burns – Sponsored by Earth Consultants International

4:15pm–5:15pm

Student and Professional Poster Presentations – Sponsored by Mount Sopris Instruments

ALL DAY

FRIDAY, SEPTEMBER 18 Technical Session #8: Dams and Levees Lessons Learned Symposium, Part II – Sponsored by University of Pennsylvania

8:15am–12:00pm

Technical Session #7: Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part II – Sponsored by University of Pennsylvania

9:00am–12:00pm

Lunch Break

12:00pm–12:15pm

Technical Session #9: Hot Topics Panel l – Sponsored by AEG Oregon Chapter

12:15pm–2:10pm

Foundation Awards & Announcement of Student Poster Competition Winners

2:15pm–2:40pm

AEG’s Corporate Business Meeting – Sponsored by LOGitEASY

2:45pm–4:15pm

Awards Ceremony – Sponsored by John Williams

4:15pm–5:15pm

SATURDAY, SEPTEMBER 19 AEG Board of Directors’ Meeting 4

9:00am–4:00pm AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

Technical Session Numbers and Names (All Times Are Central Time Zone) See page 23 for full Technical Session listings.

SESSION

TIME

WEDNESDAY, SEPTEMBER 16 Poster Presentation Videos – Sponsored by Mount Sopris Instruments

ALL DAY*

Opening Session – Sponsored by Gannett Fleming Opening Session Welcome (AEG President Cynthia Palomares)

9:00am–9:10am

2019–20 AEG/GSA Richard H. Jahns Distinguished Lecturer: Scott Lindvall

9:15am–9:45am

2020–21 AEG/GSA Richard H. Jahns Distinguished Lecturer: Cheryl Hapke

9:50am–10:20am

AEG Outstanding Environmental & Engineering Geologic Project Award: Route 30 Landslide Remediation

10:25am–11:10am

National Keynote

11:15am–12:00pm

Technical Session #1: Symposium: Engineering Geology for Tunnels and Underground Construction – Sponsored by PBS Portland

12:15pm–4:00pm

Technical Session #2: Environmental Symposium 2020: RADON Occurrence and Remediation – Sponsored by Bryan Environmental Consulting and Princeton Geoscience

12:15pm–4:10pm

THURSDAY, SEPTEMBER 17 Poster Presentation Videos – Sponsored by Mount Sopris Instruments

ALL DAY*

Technical Session #3: NOA Symposium: Hindsight in 2020 and Lessons for the Future – Sponsored by Gill Editing Online

9:00am–12:00pm

Technical Session #4: Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part I – Sponsored by Pali Consulting 9:00am–12:00pm Technical Session #5: Dams and Levees Lessons Learned Symposium, Part I – Sponsored by Schnabel Engineering

12:15pm–4:15pm

Technical Session #6: Landslide Symposium: Seeking Stable Slopes in a Time of Rapid Change – Sponsored by Landslide Technology

12:15pm–4:35pm

FRIDAY, SEPTEMBER 18 Poster Presentation Videos – Sponsored by Mount Sopris Instruments

ALL DAY*

Technical Session #8: Dams and Levees Lessons Learned Symposium, Part II – Sponsored by Schnabel Engineering

8:15am–12:00pm

Technical Session #7: Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part I I – Sponsored by University of Pennsylvania

9:00am–12:00pm

Technical Session #9: Hot Topics Panel – Sponsored by AEG Oregon Chapter

12:15pm–2:10pm

*Access anytime via author link

Student/Young Professional Session:

Get a Job & Make It Your Own: A Presentation Seeking Students’ Comments and Discussion (Sponsored By University of Pennsylvania)

Wednesday, September 16, 2020 from 12:15-1:15pm Greg Hempen, PhD, PE, RG AEG Honorary Member, Past President & 2013–14 Jahns’ Lecturer, Consulting Geophysicist, EcoBlast, LC The talk seeks to gain students’ involvement and discussion via a PowerPoint presentation. Attendees are encouraged to interrupt the presentation to comment or inquire. Three areas (Networking & Credentials, Acquiring a Job, & Career Development) are developed to touch on many concepts, chiefly to gain the comments, questions and discussions of students’ concerns. The talk and response to inquiries attempt to provide the employer’s perspective, so the new professionals may assess how their job applications and interviews might be evaluated by prospective employers. The presentation also makes a few recommendations on how one’s career over time may be tailored to that individual’s goals. Students may change the direction or develop a concern particular to that audience or to a particular industry or employment availability.

September 2020

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

The Planning Committee AEG’s 63rd Virtual Annual Meeting would not be possible without the hard work and dedication of the following volunteers.

Cynthia Palomares, AEG President Texas Engineering Extension Service, Texas A&M University

Niall Henshaw, 2020 Annual Meeting Treasurer Parsons

William Godwin, AEG Vice President Consulting Geologist

John Sager, AEG 2020 Sponsor Chair Cornforth Consultants, Inc.

Maddie German, AEG Treasurer

Mark Swank, AEG 2020 Co-Chair Aspect Consulting LLC

Nate Saraceno, AEG Secretary Digioia Gray & Associates

Mike Marshall, AEG 2020 Co-Chair Geotechnical Resources, Inc., GRI

Dave Fenster, AEG Past President Geologist, Retired

Sheri Maskow, AEG Association Manager

Sarah Kalika, AEG Meetings Advisory Committee DiabloGeo Environmental Consulting

Special Thanks AEG wishes to acknowledge the following individuals and their employers for their assistance with the planning of the 2020 Virtual Annual Meeting: Andrea Ptak, AEG News Managing Editor/Production

Heather Clark, AEG Meeting Manager

AEG Corporate Business Meeting Friday, Sept. 18 – 4:00-5:00pm This session will highlight AEG’s 2020 accomplishments and upcoming goals and projects for 2021.

We will also be introducing our new Executive Council and honoring AEG Awardees for 2020.

Symposium Conveners and Technical Session Moderators: Mark Bailey, Asbestos TEM Labs Patricia Bryan, Bryan Environmental Consultants Casey Dowling, BGC Engineering David Fenster, Retired Geologist Paul Headland, Aldea Services Greg Hempen, EcoBlast, LC Bruce Hilton, Consulting Engineering Geologist Ike Isaacson, Brierley Associates

INDUSTRY EXPERTISE භ RAPID RESPONSE භ WOMAN OWNED

Full Service Environmental Consulting

Sarah Kalika, DiabloGeo Environmental Consulting Loren Lasky, New Jersey Department of Environmental Protection Kevin McCoy, BGC Engineering Holly Nichols, California Department of Water Resources

With deep industry and technical expertise, BEC delivers costeffective environmental services and solutions through focused field investigations, clearly written reports, sound regulatory compliance strategies, sensible recommendations, and realistic cost estimates for private and public entity clients, including state transportation authorities.

Mike Piepenburg, Mott MacDonald Kevin Richards, US Army Corps of Engineers Risk Management Center Gerry Stirewalt, US Nuclear Regulatory Commission Cassandra Wagner, Bureau of Reclamation

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RUPDWLRQ FRQWDFW %(&ÂśV 3UHVLGHQW DQG )RU PRUH LQIIR Principal Geologist, Patricia Bryan at 708.922.9020(o), 312.403.0846(m), or pbryan@bryanenv.com

bryanenvv..com

AEG 2020 Virtual Annual Meeting – Program with Abstracts

Homewood, IL September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

” y l l g a n i u t y r i a St nected “V Con Using the Past to Map the Future

The 63rd AEG Annual Meeting

I’m very happy to welcome all of you to the very first “virtual” AEG Annual Meeting. This is a great way for geoscientists to stay connected with our profession and with AEG. And you can do all of this on your computer or smart phone from the comfort of your home or office.

We offer a similar agenda as previous Annual Meetings with a three-day meeting that includes an opening session with a keynote speaker, technical sessions, poster sessions, an AEG Awards event and a business meeting. We plan to move the in-person Portland Annual Meeting (which was scheduled for this year) to September 2023. But for now, sit back comfortably in your office chair or favorite chair at home and be prepared for a great virtual Annual Meeting.

A virtual platform was selected for the Annual Meeting that is very user friendly, easy to navigate, and self-explanatory. Events that you can navigate to include technical sessions on topics such as Engineering Geology for Tunnels and Underground Construction; Radon Investigation and Remediation; Naturally Occurring Asbestos: Hindsight in 2020 and Lessons for the Future; Dams and Levees: Lessons Learned; Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples; and Landslide Symposium: Seeking Stable Slopes in a Time of Rapid Change.

Other events include a Student/Young Professional networking event, Women in AWG/AEG Happy Hour networking event, Awards event and Volunteer Recognition Event. The Awards event, like all other Annual Meeting events, will be live, and participants can view your colleagues receiving their awards along with their remarks.

Don’t forget to participate in our first virtual Special Event: A terroir happy-hour with AEG Past President Dr. Scott Burns. This is a hands-on event with several wines selected in advance (that you can purchase on your own prior to the meeting) for tasting together with other participants.

I want to thank those of you that volunteered the time necessary to make this meeting possible. The 2020 Annual Meeting organizing committee has met regularly and has worked tirelessly to schedule technical sessions, and other events to make this virtual meeting a great success.

I also want to thank all the individuals and companies that have sponsored various aspects of the meeting. Without commitments like yours, these Annual Meetings would not be economically feasible or the quality would suffer. I also want to thank the many speakers, symposia organizers, and session moderators who have volunteered their time to prepare posters and technical presentations.

Finally, I want to thank all of our attendees for your participation in what promises to be another outstanding Annual Meeting.

Sincerely, Cynthia Palomares, PG, PE, AEG President, 2019–20

September 2020

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

AEG 2020 Awardees The recipents will be accepting their awards at the Awards Ceremony on Friday, September 18 from 4:15–5:15pm

Honorary Member

Douglas R. Piteau Outstanding Young Member Award:

John Peck

Amanda Forsburg

A. Keith Turner AEG confers an honor of such high esteem that the distinction is recognized as a membership class: Honorary Member. This recognition is given to those persons whose careers have exemplified the ideals of AEG.

Karl and Ruth Terzaghi Mentor Award Skip Watts Established in 2008, it recognizes outstanding individuals for their achievements as mentors throughout their career. The recipient should be an individual who has made lifelong efforts in providing professional, ethical, and technical mentoring for environmental and engineering geologists.

This award, established in 1985, is named in honor of Douglas R. Piteau is presented to a Member who is age 35 or under and has excelled in the following areas: Technical Accomplishment, Service to the Association, and Service to the Engineering Geology Profession.

Richard H. Jahns Distinguished Lecturer in Engineering Geology — 2020–21 Cheryl Hapke A joint committee of AEG and the Engineering Geology Division of the Geological Society of America selects the Jahns Lecturer, who presents an annual series of lectures at academic institutions in order to increase awareness of students about careers in Engineering Geology.

Claire P. Holdredge Award

Schuster Medal

Peter Bobrowsky

Jerry DeGraff A joint award from AEG and the Canadian Geotechnical Society that recognizes excellence in geohazards research in North America (NA).

Nominees must be residents of NA and meet at least two of the following criteria: professional excellence in geohazards research with relevance to NA; significant contribution to public education regarding geohazards; international recognition for a professional career in geohazards; influential geohazards research or development of methods or techniques; or, teacher of geohazards students.

Floyd T. Johnston Service Award Gary Luce This award is presented to a member for outstanding active and faithful service to AEG over a minimum period of nine years to coincide with Floyd T. Johnston’s tenure as Executive Director.

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and

Brian Marker

Encyclopedia of Engineering Geology The Association’s highest publication award, the Claire P. Holdredge Award, is presented to an AEG Member who has produced a publication within the past five years that is adjudged to be an outstanding contribution to the Environmental and Engineering Geology Profession.

NOMINATE a Deserving AEG MEMBER for One of Our 2021 AWARDS These are just a few of the AEG awards that recognize the contributions our members make to the Association and to the profession. For a complete list of the awards and requirements for each, visit http://www.aegweb.org/?page=Awards

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

AEG 2020 Awardees In addition to honoring outstanding AEG Members, AEG also recognizes the following:

AEG Publication Award

Volunteer Recognition

This award was established by the Association in 1968 and is presented to the author(s) of the most outstanding paper published in any AEG publication during the fiscal year. Winning papers can be viewed online at GeoScienceWorld.

William Roman Visty Dalal Niall Henshaw

Analysis of Landslide Kinematics Using MultiTemporal Unmanned Aerial Vehicle Imagery, La Honda, California

This is the time that we recognize those volunteers within AEG that have worked so hard on helping to move AEG forward over the past year or so! These awards will be handed out after the AEG Strategic Initiative Coordinators discuss committee activities and opportunities.

Jordan A. Carey, Nicholas Pinter, Alexandra J. Pickering, Carlos S. Prentice, and Stephen B. Delong Environmental & Engineering Geoscience Journal, Volume XXV, No. 4, pp. 301–317

Environmental & Engineering Geoscience Journal Outstanding Reviewer Award First presented in 2007, this award is given to an individual who has provided extended service by reviewing numerous manuscripts, including critical evaluations, detailed comments, corrections of grammar and syntax, thoughtful suggestions for changes to improve the quality of the manuscript, and guidance to the editors in making a decision regarding the manuscript.

VOLUNTEER RECOGNITION HAPPY HOUR

Wednesday, September 16 - 4:15-4:45pm Join with us to honor those volunteers without whom AEG could not function. The AEG Strategic Initiative Coordinators plan to discuss committee activities for the first part of the event, then we will hand out a few Volunteer Recognition Awards.

Zachary Leibowitz Applied Ecology, Inc.

Outstanding Student Professional Paper Andrew Graber, Colorado School of Mines – Graduate Division “Integrating Design Parameters for Reseeding and Mulching after Wildfire: An Example from the 416 Fire, Colorado.�

Environmental & Engineering Geoscience Journal, Volume XXVI, No. 4 – in press The Association acknowledges the work of geology students entered in the Student Professional Paper Contest. The award is made for papers of merit prepared in the style of the Environmental & Engineering Geoscience journal.

Outstanding Chapter Award This award was established by the Board of Directors in 2001 to honor a Chapter of the Association judged to excel in a number of areas including professional activities, communications, membership, and networking.

To be Announced at the Annual Meeting

Opening Session OEEG Project – 2018 US Route 30 Emergency Landslide Remediation Project

dd dII=] xV Y0 C BOREHOLE GEOPHYSICAL LOGGING

Put a ffuull suiitte of parraameterrss & expertiisse ex s in i lo logg in i ter t rpprreeta te t tiioon to w woork ffoor yyoou!

609.279.0008 PRINCETON GEOSSCIENCE

princetongeoscienc e.co m

See page 18‌ September 2020

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

AEG Foundation 2020 Scholars The recipients will be accepting their awards on Friday, September 18 from 2:15–2:40pm

Beardsley-Kuper Field Camp Scholarship

Christopher C. Mathewson Scholarship

Due to COVID-19, field camps were cancelled this year so scholarships will be awarded next year.

The Beardsley-Kuper Field Camp Scholarship Fund supports expenses for geology field camps with applied environmental and engineering geology components that will be useful to the students’ future profession as an environmental or engineering geologist. The scholarship was established in 2009 by Cathryne Beardsley with her daughter Dorian Kuper and son-inlaw Tom Kuper.

Carolinas Scholarship Ciara Sailar Appalachian State University Established in 2015 with a gift from the Carolinas Chapter, this scholarship supports geologic studies by undergraduate students enrolled in a geology or geoscience program at an accredited university in North Carolina or South Carolina.

Marliave Scholarship Spencer Whitman University of Nevada Reno The Marliave Scholarship Fund was established in 1968 to honor the late Chester E. Marliave, Burton H. Marliave, and Elmer C. Marliave, outstanding engineering geologists and supporters of AEG. The funds are distributed as grants, which are intended to support academic activity and reward outstanding scholarship in Engineering Geology and Geological Engineering.

Susan Steele Weir (Women of “Steele”) Scholarship Catharine Hobart Baylor University The Susan Steele Weir Scholarship Fund was established by the AEG Foundation in 2017 in order to create a scholarship fund that promotes and supports the continued development and advancement of women in the profession of engineering geology.

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Ashley Aguilar University of Texas at San Antonio

Graduate Division

Emma Fuentes Angelo State University

Graduate Division Established in 2007 as the Texas Section Scholarship, the Scholarship was renamed in 2011 to honor Dr. Christopher C. Mathewson. Recipients of the scholarship are undergraduate or graduate students enrolled in an accredited Texas college or university, or graduate students conducting field studies in Texas.

Shlemon Quaternary Engineering Geology Scholarship James Fisher Lehigh University The Shlemon Quaternary Engineering Geology Scholarship supports graduate geology students conducting Quaternary engineering geology research. Initial funding for the Scholarship was provided by a gift from Roy J. Shlemon, Honorary Member of the AEG.

Robert J. Watters Great Basin Chapter Scholarship Kathleen Rodrigues University of Nevada, Reno The Robert J. Watters Great Basin Chapter Scholarship Fund supports geoscience studies by students at the undergraduate and graduate levels.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

Martin L. Stout Scholarship

Norman R. Tilford Field Study Scholarship

Emma Palko Miami University

Angelina Han Amherst College

Undergraduate Division

Ramon Antonio Richardson

Undergraduate Division

Lauren Herbert Colorado School of Mines

Mississippi State University

Graduate Division

Undergraduate Division

Chad Neptune Tomsen Reed

California State University, Fresno

Graduate Division

Utah State University

Graduate Division

Mariliis Eensalu Edward Fordham

Northern Illinois University

Post-Graduate Division

Western Washington University

Graduate Division Dr. Martin L. Stout was Professor of Geology at California State University, Los Angeles from 1960 to 1990. He is remembered by his students for his passionate and insightful instruction in engineering geology. Dr. Stout was known for his expertise on landslides, his travels, his good humor, and his gracious manner. This scholarship supports his legacy.

The Tilford Scholarships are awarded to both undergraduate and graduate students for the summer field season, and were established in memory of Norman R. Tilford, who was a leader in engineering geology and a professor at Texas A&M University. Norm died in 1997 while flying his small aircraft to meet a student field trip. Norm was dedicated to teaching geology in the field and these scholarships support his legacy.

West-Gray Scholarship Katrina Ferry University of Kansas

Student Scholarships Are Available through the AEG Foundation The AEG Foundation manages ten funds including four scholarships. Current applications and details are available at the AEG FOUNDATION website.

DEADLINES FOR APPLICATIONS ARE FEBRUARY 1, 2021.

For more information about the AEG Foundation: https://www.aegfoundation.org/applications/

September 2020

Undergraduate Division

Samantha Tramontana City University of New York – The Graduate Center, Queens College

Post-Graduate Division Established in 2014 with initial funding provided as a gift from AEG Past Presidents Terry R. West and Richard E. Gray, this fund supports undergraduate and graduate geology students studying in the eastern half of the United States.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

Sponsors Without the help and financial support of the following individuals and companies, it would be impossible to plan the quality meeting to which AEG members have become accustomed.

Event Sponsor Gannett Fleming

Brian Greene, bgreene@gfnet.com, www.gannettfleming.com Gannett Fleming provides a full range of geotechnical and geological services, ranging from foundations, dams, and levees, to earth retaining structures, tunnels, and mining operations. These services include geotechnical analysis, digital photogrammetry, geophysics, site characterization, instrumentation, ground modification, design of earth structures, rock and soil slope stabilization, and groundwater studies. We are ISO 9001:2015 certified.

Technical Session 1 – Symposium: Engineering Geology for Tunnels and Underground Construction

PBS Portland Scott Braunsten, Scott.Braunsten@pbsusa.com www.pbsusa.com MANY SERVICES. ONE GOAL. We’re forward-thinkers who aim to innovate, create, and develop sustainable solutions for the Northwest’s engineering and environmental challenges. At PBS, we invest in the very best people and technologies to produce quality results for our clients and communities.

Technical Session 2 – Environmental Symposium 2020: RADON Occurrence and Remediation

Bryan Environmental Consultants

of environmentally impaired sites. Our employees include Professional Geologists, Licensed Site Remediation Professionals, and environmental scientists. We apply specialized tools and some unique approaches, supporting accurate risk evaluation and solutions for difficult problems—frequently including aspects such as complex geology, emerging and persistent contaminants, and receptor impacts from multiple sources. We frequently work with other consultants on multi-disciplinary project teams and are always open to new opportunities for productive collaboration.

Student/Professional Happy Hour and

Technical Session 3 – NOA Symposium: Hindsight in 2020 and Lessons for the Future

Gill-Editing Online Jane Gill-Shaler, janehgillshaler@gmail.com

Technical Session 4 – Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part I and

Student Registration Pali Consulting

Patricia Bryan, pbryan@bryanenv.com http://www.bryanenv.com

Tim Blackwood, tim@pali-consulting.com, https://pali-consulting.com/

INDUSTRY EXPERTISE. RAPID RESPONSE. WOMAN OWNED. Founded in 2014, Bryan Environmental Consultants, Inc., provides full-service environmental consulting services to private clients and municipalities. With its deep industry and technical expertise, Bryan Environmental Consultants, Inc., provides quality, costeffective environmental consulting services. We help advance your project with focused field investigations that keep your objectives in mind, clearly written reports that identify relevant environmental issues, expert regulatory advice and strategies, sensible recommendations, and realistic cost estimates.

Pali Consulting has more than 25 years of experience in geotechnical work in the Pacific Northwest and the Hawaiian Islands.

Our services include geologic hazard assessments, landslide and rockfall mitigation, geotechnical data and design reports, foundation and slope stabilization, forest practices geotechnical assessments, mse, boulder and gravity retaining wall design, foundation design and stabilization, and geotechnical forensics.

and

WOMEN IN AEG/AWG HAPPY HOUR

Princeton Geoscience Jim Peterson, jim@princetongeoscience.com, princetongeoscience.com Princeton Geoscience assists industrial clients and environmental consulting firms in the characterization and remediation 12

Wednesday, September 16 - 4:45-5:45pm Join this fun and educational happy hour to discuss diversity in the geosciences.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

Technical Sessions 5 & 8

Hot Topics Panel

Dams and Levees Lessons Learned Symposium, Part I & Part II

and

Schnabel Engineering Gary Rogers, grogers@schnabel-eng.com 336-274-9456 www.schnabel-eng.com

Student Registration AEG Oregon Chapter Oregon Chapter Board, aegoregon@gmail.com

Schnabel is a leading provider of dam, tunnel, and geotechnical engineering solutions nationally and abroad, with risk management rounding out a full-service approach. Our 400+ employee/owners in 22 locations have a passion for client service and tough technical challenges.

The Oregon Chapter is proud to sponsor the 2020 Virtual Meeting. We look forward to the interactions with our fellow geoscience colleagues and appreciate the opportunity to support student participation.

Technical Session 6

and

Landslide Symposium: Seeking Stable Slopes in a Time of Rapid Change

Student Registration AEG Sacramento Chapter

Landslide Technology

A division of Cornforth Consultants, Inc. Michael Meyer, President, mikem@landslidetechnology.com, www.landslidetechnology.com Landslide Technology, a division of Cornforth Consultants, Inc., is a Portland-Oregon based consulting firm with 37 years of experience providing complex geotechnical and geological services for transportation and civil infrastructure projects. Areas of technical expertise include: landslide investigation and stabilization; rock slope engineering and rock mechanics; emergency response to sudden slope failures; geotechnical asset management (GAM) program development and implementation; and geotechnical instrumentation.

Student/Young Professional Session: Get a Job and Make it Your Own and

Technical Session 7 – Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part II

University of Pennsylvania Yvette Bordeaux, lps@sas.upenn.edu, (215) 898-6336 https://www.sas.upenn.edu/lps/graduate/msag The Master of Science in Applied Geosciences (MSAG) offers students a specialized degree that combines knowledge in theoretical areas of geology with technical expertise in geochemistry, geophysics, hydrogeology, and engineering geology with a focus on professional development. Students pursuing their MSAG at Penn may concentrate in one of three areas: Environmental Geology, Engineering Geology, and Hydrogeology.

September 2020

Student Poster Competition

Chase White, Chase.White@conservation.ca.gov https://aegsacto.wordpress.com/ The Sacramento Chapter of AEG was the original and founding section of AEG in 1957 and proudly supports the 2020 AEG Virtual Annual Meeting and the many dedicated members of AEG across the nation.

Special Event Happy Hour: Wine and Terroir with Scott Burns and

Student Registration Earth Consultants International, Inc. Eldon Gath, gath@earthconsultants.com www.earthconsultants.com Earth Consultants International is a small geological consulting business headquartered in Santa Ana, California. We specialize in characterizing and quantifying geologic hazards for planning and engineering mitigation and are dedicated to helping our clients understand and overcome complex geologic issues all over the world. Now in our 23rd year, we have completed projects in 18 countries, in addition to hundreds of projects in southern and central California, as well as Arizona, Washington, Nevada, New Mexico, and Texas. Our two Principal Owners, Eldon Gath and Tania Gonzalez, are well recognized experts in the profession.

Services that Earth Consultants International provide include: land-use planning and feasibility studies, natural hazard assessments and hazard modeling, earthquake geology, geoarcheology, environmental and ground- water studies, mineral exploration and consulting, and litigation and geoforensic support.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

Student Registration Earthquake Insight, LLC Phyllis Steckel, psteckel@charter.net, 636-239-4013

Women in AEG/AWG Happy Hour Steele and Associates, LLC

Earthquake Insight, LLC, is a small, woman-owned business whose mission is to increase awareness of earthquake hazards, risks, and mitigation options. Audiences include those in key, decision-making, and policy-changing sectors; government and emergency professionals; as well as the general public.

Susan Steele Weir, steeleweir@aol.com 303-333-6071

AEG Corporate Business Meeting LOGitEASY

Awards Ceremony

Ansis Guslens, ansis@logiteasy.com https://logiteasy.com LOGitEASY web-based soil logging and boring log software (LOGitEASY eForm) is usable both in the field and in the office, for transferring field notes. Boring logs can be produced in a variety of templates, including LOGitEASY, gINT, LogPlot, and others. Digital data files can be downloaded for use in other boring log applications or databases. Once boring logs are finalized, they can be viewed on a geographic map and used to create free geologic cross sections online. Site Location maps and site plans can also be generated online, integrating borehole locations on aerial or terrain backgrounds with the ability to show additional site features, either imported from Google Earth, survey data, or drawn by hand. Plans are automatically generated on a standard title block with company logo and project information. LOGitEASY drafting services convert handwritten field notes into gINT, LogPlot, or custom template logs on fixed-price basis. Our other free tools online include USCS Code Calculator, Munsell Color Translator, and Soil Logging Field Forms.

AEG Technical Session #2 Speakers AEG New York/Philadelphia Chapter Jim Peterson, 609-279-0008 http://aegnyp.org/ The New York to Philadelphia (NY-P) Chapter addresses an everincreasing interest in applied geology in the United States, in both the development and restoration of the earth. Membership in AEG NY-P can enhance your technical and business knowledge, provide career opportunities, and introduce you to thousands of other professionals... all while having fun in the process!

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Steele and Associates, LLC, is a small woman-owned engineering geologic consulting firm providing peer review of dam and tunnel construction projects and consultation on slope stabilization projects.

and

AEG Volunteer Recognition Happy Hour John Williams, john.williams@sjsu.edu

Poster Presentations Mount Sopris Instrument Company, Inc.

Leading manufacturer of borehole geophysical logging systems for Groundwater, Environmental, Geotechnical, Energy, and Research Industries

PROBES WINCHES LOGGERS SOFTWARE ONLINE STORE Learn more at

MOUNTSOPRIS.COM +1 303.2792 .321 1

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

F

AEG is excited to host its first ever Virtual Annual Meeting!

or the first time in AEG’s history, we had no choice but to cancel the in-person 2020 Annual Meeting as originally planned for this September in Portland, Oregon due to the nation’s collective response efforts to COVID-19 and due to the Governor of Oregon mandating that no large gatherings take place through September 2020. We have replaced the anticipation of our Annual Meeting with the same zeal for a new and unprecedented opportunity to adapt and serve our members and the geology community.

The 2020 Planning Committee has put together a technical program that is sure to provide an outstanding educational experience for attendees. PDHs and CEU credits will be available for all technical sessions. AEG provides an open forum for the presentation of varying opinions and positions.

However, opinions and positions expressed by speakers do not necessarily represent the views or policies of AEG. All sessions will be recorded so you can view them at any time. Don’t miss this chance to learn from the experts, all from the comfort and safety of your home computer!

Opening Session Wednesday – 9:00am–12:00pm

2019–20 JAhns Distinguished Lecturer – Scott Lindvall Scott received his BS in Geology from Stanford University in 1984 and his MS in Geology from San Diego State University in 1988. Dick Jahns was Scott’s undergraduate advisor at Stanford, which makes this award especially meaningful to him. He has spent the majority of his career working for consulting firms specializing in seismic hazards and engineering geology.

He currently manages the Lettis Consultants International southern California office.

His interest in geology came at a young age growing up in the Transverse Ranges of southern California. His geologist father, Eric Lindvall, helped instill an appreciation of the outdoors (and therefore geology) and was later instrumental in shaping Scott’s career. His interest in earthquakes was triggered at nine years old in the early morning hours of February 7, 1971, with September 2020

Jahns Distinguished Lecturer Scott Lindvall pauses to enjoy a Kodak moment while mapping in California’s Owens Valley.

the M6.6 San Fernando earthquake. Experiencing strong ground shaking from the main shock and several large aftershocks in the epicentral region, while dust was slowly rising from rock falls in the surrounding canyons, left a lasting impression.

Scott has performed detailed mapping of surface ruptures of earthquakes in southern California and Turkey, including the 1986 M6.6 Superstition Hills, 1992 M7.3 Landers, 1999 M7.4 zmit (Kocaeli), 1999 M7.1 Düzce, and the 1999 M7.1 Hector Mine earthquake ruptures. Scott’s experience in neotectonics, paleoseismology, and geomorphology has enabled him to pursue research projects designed to better

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AEG 2020 VIRTUAL ANNUAL MEETING quantify the timing of past events, slip rate, surface displacement, and style of deformation on active strike-slip and reverse faults throughout southern California. He has been awarded over a dozen research grants funded by the U.S. Geological Survey National Earthquake Hazards Reduction Program (NEHRP) and the Southern California Earthquake Center (SCEC).

Scott has directed geologic evaluations and seismic source characterizations in a variety of tectonic environments ranging from active plate boundaries to stable cratons. He served on the Technical Integration Team for a multi-year study sponsored by the US Nuclear Regulatory Commission, US Department of Energy, and the Electric Power Research Institute to develop the Central and Eastern United States Seismic Source Characterization for Nuclear Facilities, which has served as the regional seismic source model for hazard evaluations of nuclear facilities since its publication in 2012. Scott has also served on the advisory committee of the EarthquakeInduced Landslides Working Group for the California Geological Survey’s (CGS) Seismic Hazards Mapping Program and, more recently, the CGS Special Publication 42 Advisory Panel to update the regulatory guidance on assessing fault rupture hazards in California.

Annual Meeting Presentation Crossing the San Andreas Fault: Improving the Resilience of the Los Angeles Aqueduct System This talk focuses on the Los Angeles Aqueduct crossing of the San Andreas fault in the Elizabeth Tunnel and describes the detailed surface and subsurface geologic investigations used to characterize the architecture of the fault zone at tunnel depth.

Historic fault displacement data from global strike-slip faults are presented along with deterministic and probabilistic fault displacement hazard analyses performed to address the new 2019 performance-based seismic design guidelines for the Los Angeles Department of Water and Power.

2020–21 Jahns Distinguished Lecturer – CHERYL HAPKE, PHD Dr. Cheryl J. Hapke has decades of experience in studies of coastal geology and processes of coastal change as they relate to societal issues. She is presently the coordinator of the Florida Coastal Mapping Program and holds a research professorship at the University of South Florida’s College of Marine Science. She also runs a private consulting company: Coastal Science Solutions. She earned her PhD in coastal geology from the University of California, Santa Cruz and spent over 20 years as a research scientist with the US Geological Survey before taking early retirement from federal service in 2019. Her expertise spans a variety of coastal geomorphic settings, including barrier islands, rocky coastlines, and carbonate coasts. She currently is focused on helping coastal communities with sea-level rise adaptation planning.

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Cheryl Hapke PhD atop the high dunes at Fire Island National Seashore, NY

Annual Meeting Presentation Our Changing Coastlines: The Intersection of Geologic Processes & People Dr. Hapke’s presentation will provide a glimpse into the professional career of a research scientist whose passion of coastal geology has taken her from the steep slopes of the Big Sur Coast to the barrier islands of NY battered by Hurricane Sandy to the island beaches of the Gulf of Mexico. Regardless of the location or the geomorphology of the coastline, Dr. Hapke explores how coastlines change in response to storms, tides and sea-level rise, focusing on the vulnerabilities that changing conditions bring to communities, infrastructure, and the natural environment around them. Over the course of her lecture series, she will explore how geology and humans intersect at the coast and how science can be used not only to understand how a coastal system works but also how that knowledge can be used to help managers, planners, and decision-makers best balance natural processes and societal needs.

In Need of Professional Development Hours?

Take advantage of earning up to 2 CEU Credits and 20 PDHs offered throughout your entire Virtual AEG Annual Meeting experience at an incredible value!

The best part: Credits will be available for all educational sessions—regardless if you listen live or later!

Please visit our website for all of the details, www.aegannualmeeting.org.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

AEG GEOLOGY TRIVIA CONTEST

NORTH FORK DAM / ASHEVILLE, NC

Join us for a fun Geology Trivia contest during each of the meeting breaks. We will be sending a link to the contest to all participants. AEG Logo Merchandise certificates will be awarded to the winner of each break. Don’t miss this fun way to take a brain break from the sessions. We’ve shown a few items here, but there’s so much more: https://aegweb.logosoftwear.com

Integrated dam, geotechnical, and tunnel engineering solutions ranging from subsurface explorations and soil testing to project risk management, engineering analysis, design, and construction support. schnabel-eng.com

September 2020

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

AEG Outstanding Environmental & Engineering Geologic Project Award

Route 30 Landslide Remediation

Project Team: Pennsylvania Department of Transportation, Gannett Fleming, Inc., & Golden Triangle Construction Co., Inc.

National Significance of Project US Route 30 is a major eastwest, coast-to-coast highway. The roadway is the third longest US highway, extending 3,073 miles across the northern tier of the US from Atlantic City, New Jersey, to Astoria, Oregon. The portion of Route 30 running through Pennsylvania, the Lincoln Highway, is perhaps the most famous of all the US highways and is known as one of the earliest transcontinental highway routes for automobiles across the US Today. The route still connects the Commonwealth’s two largest cities—Philadelphia in the east and Pittsburgh in the west.

On April 6, 2018, on a four-lane stretch of the Lincoln Highway located in East Pittsburgh Borough, Allegheny County, engineers from the Pennsylvania Department of Transportation (PennDOT) and Gannett Fleming were investigating a troubled section of Route 30.

The roadway, a principal artery between the suburbs and downtown Pittsburgh, was experiencing surface displacement problems.

The investigation revealed much more than expected. The team detected a crack in a retaining wall near the base of the slope below the highway, as well as signs that the retaining wall 18

was beginning to shift—evidence that accelerating surface movements identified at the roadway grade, may be the result of underlying slope movement. Recognizing imminent danger, the team alerted police to evacuate a residential community at the base of the slope.

Within hours and shortly before daybreak on April 7, a landslide sent 300 feet of roadway and thousands of tons of soil plummeting 90 feet down the steep hillside, destroying a home and two apartment buildings.

Project Description The team’s decisive action to protect the public and remove residents from harm’s way likely saved dozens of lives. Police evacuated more than 30 residents from six apartment buildings. Some stayed with family, and PennDOT made accommodations for the remaining displaced residents to be either permanently relocated or provided long-term temporary housing until such time that the area could be stabilized, allowing the residents to return to the unaffected buildings.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

Problem Solved

A landslide sent 300 feet of Route 30 and thousands of tons of debris plummeting down a steep hillside, destroying residences below. Engineers investigating roadway subsidence had initiated an evacuation just hours earlier.

Fortunately, no injuries occurred due to this catastrophic failure. However, the closure of this major highway threatened to paralyze the region. In the days after the landslide, residents across the region were dismayed to learn that large highway projects often take years to get off the ground, and months to construct. This key stretch of Route 30 connecting North Versailles, East McKeesport, and North Huntingdon to the Parkway East near East Pittsburgh carries an estimated 30,000 travelers every day—many going to downtown Pittsburgh for work.

Alternate routes could not accommodate the additional vehicles without widespread delays and wear and tear on local roads.

Even a year-long closure of Route 30 would have been a distressing hardship for daily commuters who depend on the highway. The collapse not only severed suburban communities from each other, it cut off convenient access to center city workplaces for tens of thousands of residents. A fast-track solution was needed to restore regional mobility as quickly as possible. After a brief site assessment for continued slope movement, the monumental task of rebuilding Route 30 was underway.

To restore the key artery and return displaced residents to their homes as quickly as possible, PennDOT partnered with Gannet Fleming and their on-call geotechnical maintenance contractor, Allison Park Contractors (APC), to perform investigation and design concurrently with emergency cleanup operations.

Working around the clock, Gannett Fleming delivered a comprehensive landslide remediation design and bid package in just 10 days—when the industry norm is 10 weeks or more, even under emergency conditions. During this time, APC also performed dusk to dawn demolition of damaged structures and careful excavation of landslide debris. This extraordinary effort kicked off final construction operations that continued 7 days a week, 24 hours a day, with no holiday breaks, allowing the highway to reopen in less than three months, instead of a more typical design and construction duration of two years.

The comprehensive package included: ■ details for excavation and benching to remove the landslide material and replace it with durable rock embankment ■ final structure plans for construction of a 400-ft-long, 20-ft-high anchored soldier pile and lagging retaining wall to support the new embankment ■ design-build roadway plans for roadway surface and drainage repairs ■ special provisions needed for PennDOT to advertise the project for bid Reopening Route 30 just 80 days after the landslide restored regional mobility as quickly as possible. Former PennDOT Secretary Leslie S. Richards praised the powerful teamwork and creative engineering that led to the remarkable accomplishment. “The intense dedication shown by everyone assisting those impacted by the slide and reopening this roadway has been astounding.”

The team’s construction cost estimate was only 1% off the accepted bid, more accurate than the 10% goal of a typical estimate, and extremely rare for one prepared under such an aggressive schedule. Careful analysis of similar construction projects and knowledge of emergency construction costs allowed the team to provide PennDOT with a precise estimate in 10 days, helping the client plan budget needs accurately.

Budgeted Cost: $6.5 Million Actual Cost: $6.5 Million Scheduled Completion Date: 6/30/2018 Actual Completion Date: 6/27/2018

Environmental and Engineering Geologic Principles Applied The delivery of a comprehensive remediation design and bid package to PennDOT within a two-week timeline enabled the reopening of the rebuilt highway just three months after the landslide occurred.

September 2020

The engineers used an unconventional, aggressive approach to design a 400-ft-long retaining wall and 90-ft embankment, working together with PennDOT and emergency excavators as they began removing approximately 35,000 cubic yards of debris from the site. Although excavation began almost immedi-

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

The landslide severed a key travel artery connecting eastern suburban communities to the Parkway East and downtown Pittsburgh. The highway has an average daily traffic count of 30,000 in the project area.

Debris removal began almost immediately. The design team worked closely with excavators so that drill rigs could access core sample borings along the planned alignment of a new retaining wall.

ately, the team could not wait until debris was removed to begin geotechnical investigations and analyses; or until analysis was complete to begin wall design—standard procedure on most projects. By analyzing data and developing the design simultaneously, the team demonstrated an innovative application of existing techniques to achieve a successful solution in an exceptionally short period of time.

Sandstone outcroppings above the roadway on either side of the landslide offered valuable clues about subsurface conditions. A record drawing of the existing roadway profile corroborated visual observations and identified the probable limits of 20

the impacted area. Knowledge of local bedrock stratigraphy, observations of outcrops on adjacent valley walls, and the known depth of an existing stream in the valley helped the team estimate subsurface conditions and the declination of the bedrock. This ingenious geotechnical and geological detective work allowed design work to begin within hours of the roadway’s collapse.

With the geologic units loosely defined, Gannett Fleming prepared a subsurface model consisting of a durable sandstone bedrock at the roadway level. This model was based on outcroppings observed that were underlain by very weak claystone units and colluvial clay deposits across an infilled valley.

The thickness of the weak claystone unit and depth to a target underlying shale bearing unit was estimated based upon the geotechnical engineers 25 years of experience working in the region, with reliance on specific bedrock unit thicknesses and engineering strength properties, as obtained from previous projects. This information was corroborated with expanded estimates from the published works of other geologic professional works from within the landslide-prone sedimentary deposits of the Pittsburgh region.

At the team’s direction, excavators removed debris from specific areas to enable drill rigs to access nine core sample borings along the anticipated wall alignment. Geotechnical engineers analyzed samples on the spot to determine how actual conditions aligned with the estimates. Data was conveyed instantly from the field to designers, who refined the design models as needed.

To hit the two-week deadline, engineers gathered as much data on subsurface conditions as quickly as possible, even though layers of rubble still covered the site. They also began wall design immediately, using the data on hand, and continually adjusted the design as new data became available. The unique approach enabled rapid progress.

Available lidar imagery provided site mapping and surface contours and cross sections were cut through the landscape to identify the ground surface prior to the landslide. Mapping was supplemented by 3D aerial photogrammetry using a drone launched within days of the slope failure. With this information in hand, the team created a framework for remediation design options to present to PennDOT. The details of the retaining wall size, type, and location were then confirmed or adjusted as new information became available.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

ABOVE AND TOP RIGHT: Careful calculation and planning enabled wall construction as close as 25 feet to undamaged apartment buildings, preventing their removal and allowing the wall to be positioned exactly as designed.

Protection and Enhancement of the Environment To minimize the environmental impact to the small urban community of East Pittsburgh, the team designed a durable rock embankment supported by an anchored wall. This remedial option was provided to keep the footprint of the reconstructed embankment as small as possible.

PennDOT didn’t settle for simply fixing the immediate problem. Approximately 300 feet of roadway collapsed, but the team recognized that the landscape immediately adjacent to and above the remaining apartment buildings consisted of similar weak, landslide-prone soils. To enhance the project’s protection of the local environment, the team added a wall extension to the project scope. The proposed retaining wall was extended by 150 feet, behind the remaining buildings, to stabilize the weak natural soils and prevent another environmental catastrophe from occurring. This also helped quell residents’ concerns upon returning to their homes.

Additionally, 500 feet of the highway was replaced to ensure that segments on either side of the collapse blended smoothly back into the adjacent landform and were firmly supported by a solid foundation.

September 2020

The finished embankment consists of 40,000 cubic yards of durable rock fill to provide long-term roadway support in a region known to have weak claystone soil, which is prone to landslides.

Benefit to the Public Fifty-four contractors and vendors attended the pre-bid for the project, and after 13 days from the original slide, bids were officially opened. Golden Triangle Construction (GTC) was the low bidder at $6.5 million. GTC used a proactive approach to complete construction within the tight timeline. Based on preliminary contacts made by Gannett Fleming, the contractor found a supplier that had in stock the 51 steel beams required for the retaining wall. They understood the importance of the project, so they took a gamble and locked up the steel prior to getting the bid.

GTC immediately stepped into action, relieving PennDOT’s on-call emergency contractor, they continued the landslide debris removal and excavation operations. Working with their previously assembled team of subcontractors and vendors, GTC also began drilled shaft work within 23 days of the bid date. This team was remarkable in the fact that the galvanized soldier piles were delivered and installed in conjunction with the shaft work. The tie-back anchor activities occurred 12 days after the drilled shaft start date, which is further testament to great organization, scheduling, and teamwork. During those

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

A 400-foot-long, 20-foot-high, anchored soldier pile and lagging retaining wall supports the embankment, protecting nearby residences from future ground movements.

activities, 30,000 cy of PTM 510 rock and 14,000 cy of foreign borrow were delivered to the site and placed as the drilled shaft concrete cured. The road reconstruction and drainage were the last activities to occur, and by June 27, 2018, all physical work required to open US Route 30 was complete.

PennDOT Right-of-Way staff, along with Allegheny County Emergency Services and disaster relief organizations, were working behind the scenes during this timeframe assisting the 31 evacuated residents. They worked day and night to ensure the displaced residents were provided with housing and essential needs. All apartment residents were displaced until construction was completed, and 11 of those residents’ apartments or homes were destroyed.

The remediation of the US Route 30 landslide and the attendance to the displaced residents were the epitome of the ultimate partnering and cooperative experience. Although not without challenges, the urgency and importance of the project was understood by all, and this project was completed three days ahead of an extremely aggressive schedule, and without injury. This could not have been achieved without the collaborative partnership between the designer, the multiple contractors, and vendors involved on the project, PennDOT, and the Federal Highway Administration.

“I want to thank PennDOT’s crew for their countless hours and tireless efforts to get this project done quickly and safely. I am proud of the work we’ve all done together,” said Tom Wolf, Governor of Pennsylvania.

Advancement of Public’s Understanding of Geology and Engineering Geology Route 30’s catastrophic failure was a catalyst to increase funding awareness for landslide recognition, mitigation, and avoidance efforts throughout western Pennsylvania. Both the governor of Pennsylvania, Tom Wolf, and the now former secretary of transportation, Leslie S. Richards, visited the site in the days following the slope failure to provide support for the first responders and acknowledge the quick action by local PennDOT officials and 22

engineers. This public action provided a call to action for municipalities, infrastructure owners, and engineers to recognize the increased risk of landslides throughout the area and increase education and identification efforts to reduce or prevent such events from impacting communities in the future.

Following completion of this project, a regional Landslide Task Force consisting of state, county, and city officials was instituted. The group’s mission is to further discuss and educate local municipalities and other interest groups regarding local geologic conditions and resources available for identifying landslide-prone areas and historic landslides. Some of these resources have been upgraded to a user-friendly GIS platform and published on websites for easy public access.

PennDOT, Gannett Fleming, and Golden Triangle Construction have presented this project to several local, regional, and national technical groups, associations, and educational forums to share knowledge and lessons learned during the landslide repair. Each presentation explained the geologic setting and conditions under which the soil became dangerously unstable, which in this case involved regionally weak claystone units and colluvial deposits, and record amounts of precipitation. These presentations and seminars focus on advancing the community’s understanding of how geology and engineering principles developed from the study of geologic deposits impact our infrastructure.

Enhancement of Local Cultural and Historical Understanding Local universities also have become actively engaged in further study and understanding of landslide-prone areas and the processes used to identify, evaluate, and address marginally stable soils or weak bedrock units to limit risks of future impact to infrastructure or other developments. The university groups are preparing seminars to bring together owners, experts, and regulators to share knowledge and experience. Special groups are also being formed to engage faculty, students, and practitioners, and other interested stakeholders. Together, these groups can share and discuss data, processes, and current practices in an attempt to develop innovative methodologies or materials that may be used to effectively mitigate or prevent landslide impacts to infrastructure.

Summary The Route 30 Emergency Landslide Remediation project is a testament to the engineering profession that in the face of a crisis, the civil engineering community, consisting of the owner, emergency responders, design engineers, and construction contractors, can come together as a team to accomplish a common goal in a time frame that was deemed unattainable to many.

Former PennDOT Secretary, Leslie S. Richards notes, “I know when I look back at my career as PennDOT secretary, this project is going to be one of the examples I give to show how PennDOT works with our communities in getting projects done.”

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 61ST ANNUAL AEG 2020 MEETING/IAEG VIRTUAL ANNUAL XIII CONGRESS MEETING

Technical Program Schedule (All Times Are Central Time Zone)

Wednesday, September 16 – Afternoon Technical Session #1

Symposium: Engineering Geology for Tunnels and Underground Construction (Sponsored by PBS Portland) We will open this session with a 60–minute presentation by our Keynote Presenter Dr. Ed Cording, who will discuss the early days of engineering geology in underground practice, the development of the many key tenants of our work, and then fast forward to the continued application of our ability to observe and record our findings in ever-increasingly more challenging work conditions. With over 60 years of experience in the field and around the world, Dr. Cording will present valuable lessons and insights for the listeners. Four other presentations will follow and cover a wide range of topics (large and small diameter tunnels) and ground conditions (soft ground and rock) including tunneling through carbonate reef structures and shale, developing a design for a microtunnel drive around a vertical curve through waterbearing sediments, and using directional drilling to locate old historic tunnels in the Rocky Mountains. With a wide variety of locations, tunnel sizes, and ground conditions, we hope there will be something of interest for all of our colleagues and hope you will join us.

Conveners: Paul Headland, Ike Isaacson, and Mike Piepenburg Time

Speaker

Title

12:15–1:15

Ed Cording

Tunneling Group Keynote

1:15–1:40

Ike J. Isaacson

Identification and Adverse Impacts of Carbonate Reef Structures for Tunnel Projects

1:40–2:00

Michael Piepenburg

Behavior of the Chagrin Shale in Selected Tunneled Excavations, Cleveland, Ohio

2:15–2:45

Paul Headland

King City Siphon – Challenging Ground Conditions Drive Alignment Selection for a Vertical Curve Microtunnel

2:45–3:15

Ashton Krajnovich

Historic Analysis and Future Expansion of the Eisenhower-Johnson Memorial Tunnels, Part 1: Geologic Modeling

3:15–3:45

Gauen Alexander

Historic Analysis and Future Expansion of the Eisenhower-Johnson Memorial Tunnels, Part 2: Geotechnical Analysis

3:45–4:00

Q&A

Technical Session #2

Environmental Symposium 2020: RADON Occurrence and Remediation (Sponsored by Bryan Environmental Consultants and Princeton Geoscience) AEG’s Virtual Environmental Symposium 2020 will focus on radon, a naturally occurring, radioactive and carcinogenic emerging contaminant. This half-day symposium will feature an invited panel of radon experts from academia and industry. Four in-depth presentations will highlight the latest USGS radon mapping results and discuss the cutting-edge remediation techniques available now for mitigation of radon, both in indoor air and in drinking water.

Conveners: Loren Lasky and Patricia Bryan Time

Speaker

Title

12:15–1:05

Scott Burns

Radon – The Invisible Killer – Geologic Characteristics That Lead to High Radon Production

1:10–2:00

David Innes

New Technologies for Testing and Mitigating Radon in Air, Plus a Radon-101 Review of Health Effects

2:15–2:50

Zoltan Szabo

Radon-222 Occurrence in Groundwater is Highest in Appalachian Piedmont, Eastern USA, and Correlates to Lead-210 Occurrence

2:55–3:30

John Noyes

How Training and Education in Radon Mitigation Has Provided Invaluable Insights for Vapor Mitigation: Supported by Three Case Studies

3:35–4:10

Jennifer Athey

Alaska Radon Testing and Occurrence: Now That We Know Better, We Are Working To Do Better

September 2020 2018

AEG Annual 2020 Virtual Annual Meeting – Program with Abstracts AEG 61st Meeting/IAEG XIII Congress – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

Thursday, September 17 – Morning Technical Session #3

NOA Symposium: Hindsight in 2020 and Lessons for the Future (Sponsored by Gill Editing Online) Asbestos occurs naturally across the United States and around the world within mafic and ultramafic rocks as well as soils derived from these rocks. Join us to learn about naturally occurring asbestos (NOA) and elongate mineral particles (EMPs), what minerals are regulated as asbestos, where they are typically found, sampling and analysis methods, health effects from inhalation, and the varying regulations that apply to construction workers, the public, and waste soil. We will additionally discuss emerging issues relating to efforts to further define worker protection procedures and limit the use of asbestos in consumer products.

Conveners: Sarah Kalika and Mark Bailey Time

Speaker

Title

9:00–10:00

Mark Bailey

An Overview of Analytical Test Methods for NOA

10:00-10:30

Thomas Zdeb

An Overview of Key Things to Consider When Designing a Construction Project Involving Naturally Occurring Asbestos (NOA) – Setting the Stage For Success.

10:30-10:50

Oliver Barker

Towards a Model for the Permanent Eradication of Mine Related Asbestos Pollution in South Africa

10:50-11:30

Sarah Kalika

Asbestos Monitoring in Construction Site Air – Unexpected Challenges to Construction Site Monitoring

11:30-11:50

Erell Leocat

Carto PMAi – A Project to Evaluate Worker and Public Populations Exposure to Elongate Mineral Particles of Interest

11:50-12:00

Q&A

Technical Session #4

Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part I (Sponsored by Pali Consulting) This technical session will focus on oral presentations that showcase a broad spectrum of practical examples illustrating how a range of geoscientific methods were creatively and innovatively applied to evaluate potential problems, collect and evaluate data pertinent to those problems, propose solutions to resolve them, and communicate information in a manner that enables all interested stakeholders to understand the geoscientific basis for the proposed solutions.

Conveners: Gerry L. Stirewalt and David F. Fenster Time

Speaker

Title

9:00–9:20

Gerry Stirewalt

Introduction to the Session on Applied Geoscience Methods for Problem Solving

9:20–9:40

Issac Pope

Reaching New Heights: The Cascade Volcanoes as Exemplary Laboratories for Applied Geoscience

9:40–10:00

James Arthurs

Post-eruption Transportation Repairs at Hawaiîan Volcanoes National Park

10:00–10:20

Jenise Thompson

The Reactor and the Volcano: A Risk-Informed Approach of the NRC to Assess Volcanic Hazards at New Nuclear Reactor Sites

10:20–10:40

Patrick Pringle

Tree-Ring Analysis (Dendrochronology) – A Tool for Dating of Subfossil Forests – Victim Tree Examples from Mount Rainier Lahars and the Bonneville Landslide

10:40–11:00

Leon van Paassen

Microbially Induced Desaturation (MID), a New Method to Mitigate Earthquake-Induced Liquefaction

11:00–11:20

Iuliia Tcibulnikova

Permafrost Degradation as Geological Engineering Challenge in Alaska: Application of Remote Sensing Techniques

11:20–11:40

Morley E. Beckman

Finding the American Tunnel: Using Directional Drilling Techniques to Intersect Abandoned Mine Workings

11:40–12:00

Timothy Blackwood

Addressing Geologic Hazards in the Newell Creek Canyon Natural Area through Avoidance, Accommodation, and Mitigation

SPECIAL EVENT HAPPY HOUR WITH SCOTT BURNS: WINE TASTING AND TERROIR Thursday, Sept. 17 – 4:15-5:15pm

Escape the office for an evening and join us. Our very own Dr. Scott Burns will lead the wine tasting as he explains the importance of terroir—that is the relationship between geology, soil, climate, and wine. Scott is the past IAEG President, past AEG President, and has established himself as the local expert on terroir in Oregon’s Willamette Valley. We will be providing a wine list of affordable Oregon Wines that can easily be purchased at your local grocery store. Please join us for what promises to be a fun and memorable evening as we showcase Oregon region’s geology and wine!

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AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 61ST ANNUAL AEG 2020 MEETING/IAEG VIRTUAL ANNUAL XIII CONGRESS MEETING

Thursday, September 17 – Afternoon Technical Session #5

Dams and Levees Lessons Learned Symposium, Part 1 (Sponsored by Schnabel Engineering) Risk Assessments for Dams – led by a keynote presentation by Doug Boyer with FERC, who will be discussing the evolution of risk-informed decision making and where the industry is headed. Dam Remediation and Investigations – led by a keynote presentation by Brian Greene with Gannett Fleming, who will discuss the recent installation of a cutoff wall at the East Branch Dam in Wilcox, Pennsylvania. Levee Risk Assessments, Incidents, and Repairs – led by a keynote presentation by Dave Rogers with Missouri University of Science and Technology, who is well-versed in levee case histories.

Conveners: Bruce Hilton and Holly Nichols Time

Speaker

12:15–12:20

Introduction

12:20–1:00

Douglas Boyer

Keynote: Current Status of Risk-Informed Decision Making for Dam and Levee Safety Programs

1:00–1:20

Matthew Balven

Dam Failures in Hindsight. Lessons Learned?

1:20–1:40

Scott Walker

The Wheeler Dam Lock Failure: A Case History

1:40–2:00

Suzanne Hess-Brittelle

Phased Approach for Evaluating Piezometers to Inform a Risk Assessment, Blakely Mountain Dam, Ouachita River, Arkansas

2:15–2:55

Brian Greene

History of Internal Erosion at East Branch Dam, Pennsylvania, and Cutoff Wall Remediation Project

2:55–3:15

Philip Shaller

Construction, Operation, and Failure of Ka Loko Dam, Kauai, Hawaii

3:15–3:35

Scott Walker

The Hales Bar Project: Construction, Mitigation, and Removal of a Dam Founded on Karst

3:35–3:55

Visty Dalal

“From Scoured to Safety” – Rehabilitation of Lake Roland Water Supply Dam, Baltimore, Maryland

3:55–4:15

John Mundell

Geophysical Evaluation of Dam Seepage to Support Rehabilitation Efforts

September 2020

Title

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING

Thursday, September 17 – Afternoon Technical Session #6

Landslide Symposium: Seeking Stable Slopes in a Time of Rapid Change (Sponsored by Landslide Technology) This symposium will present case studies and field-based research of landslide processes and landslide hazard evaluation, management, mitigation, and risk reduction in the frameworks of historical and contemporary societal needs. Topics include field studies of landslide activity, morphology, and geometry; comparative evaluation of historical and contemporary mining-related geohazards from a technical and social standpoint; and impacts of climate change on landslide processes.

Conveners: Kevin McCoy and Casey Dowling Time

Speaker

Title

12:15–12:20

Introduction

12:20–12:40

Paul Santi

Environmental and Geologic Hazards near Small-Scale Gold Mines in Peru: An Analog for 19th and Early 20th Century Mining in Colorado

12:40–1:00

Anna Stanczyk

Permafrost Thaw, Precipitation, and the Pretty Rocks Slump – A Climate Change Induced Landslide in Denali National Park?

1:00–1:20

Frank Jordan

Interrelationship of Faulting and Landsliding in the San Bernardino and San Jacinto-Santa Rosa Mountains

1:20–1:40

Rory Robinson

Prevention and Recording of a Large Landslide Event Using Ground-Based Interferometric Radar at Roberts Mountain, Oregon

1:40–2:00

Rory Robinson

US Highway 20, Between Pioneer Mountain and Eddyville, Oregon: The Observational Design Approach, Now Post-Construction

2:15–2:35

Yonathan Admassu

Lessons Learnt From the Use of Google Earth/Google Street View for Rockfall Hazard Rating

2:35–2:55

Luke Weidner

Automated Rock Slope Monitoring: Lessons from the Colorado Rockies

2:55–3:15

Vishnu Chakrapani Lekha

Improving Satellite-Based Precipitation Using Rain Gauge Observations for Landslide Prediction in a Data Sparse Region

3:15–3:35

Jennifer Bauer

Landslide Features on the WNC Blue Ridge Escarpment – It’s a Complex Issue

3:35–3:55

Trent Hubbard

Debris Flow Inventory and Hazard Assessment in Sitka, Alaska

3:55–4:15

Larry D. Gurrola

Flood History and Landslide Dam Hazards of the Montecito Watersheds, Santa Barbara County, California

4:15–4:35

Andrew Mitchell

Effect of Multi-stage Failures on Rock Avalanche Mobility: Joffre Peak Case Study

Friday, September 18 – Morning Technical Session #7

Applied Geoscience Methods for Problem Solving – A Gallery of Practical Examples, Part II (Sponsored by University of Pennsylvania) Conveners: David F. Fenster and Gerry L. Stirewalt Time

Speaker

Title

9:00–9:20

Samantha Farmer

Analysis of High Priority Unstable Rock Slopes in Great Smoky Mountains National Park, Tennessee and North Carolina

9:20–9:40

Margaret Kroehler

Preliminary Investigation of Slope Movements in the North Cove Area, North Carolina

9:40–10:00

Arpita Nandi

Soil Creep and its Role in Mudslide Generation – Case Study from Erwin, Tennessee

10:00–10:20

Nicholas Ferry

Influence of Bedrock Substrate on Mobility of Large Rock Avalanches Formed in Dry Climates: Blue Diamond Landslide Case Study

10:20–10:40

Dylan Hemraj

Development of a Geotechnical Model for Open Pit Slope Design in Cenozoic Sediments in the Pilbara region of Australia

10:40–11:00

George Freitag

Pumice Mine Reclamation, Oregon State University – Cascades Campus, Bend, Oregon

11:00–11:20

Edmund Medley

Recent Advances in Stochastic Analyses of Slopes in Bimrocks and Bimsoils

11:20–11:40

Echo Li

A Machine Learning Algorithm for Rock Mass Characterization and Stability from Point Clouds

11:40–12:00

Jacqueline Sosa

Preparing for The Big One: Data-Driven Spatio-Temporal Risk Maps for Earthquake Evacuation in LA County

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AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 61ST ANNUAL AEG 2020 MEETING/IAEG VIRTUAL ANNUAL XIII CONGRESS MEETING

Friday, September 18 – Morning Technical Session #8

Dams and Levees Lessons Learned Symposium, Part II (Sponsored By Schnabel Engineering) Conveners: Kevin Richards and Cassandra Wagner Time

Speaker

Title

8:15–8:20

Introduction

8:20–9:00

J. David Rogers

Site Characterization of Levee Foundations

9:00–9:20

John Mundell

Calibrating Artificial Intelligence and Hydrologic Modeling with Smart Monitoring Inputs for Enhanced Levee Safety Predictions under Changing Climate Conditions

9:20–9:40

Kevin Hayes

Hydrogeologic Characterization of the C-24 North Reservoir Dam Site, Indian River Lagoon–South Watershed, Florida

9:40–10:00

Scott Burch

Assessment of 14 TVA Spillways and the Evaluation of Erodibility for Earth Cut Spillways

10:00–10:20

Michael George

Back-Analysis of Unlined Rock Spillway Erosion Rates to Support Risk-Informed Design

10:20–10:40

Stephanie Briggs

Unlined Spillway Erosion, Contributions from Hillside Channel Flow and Local Impinging Jet Scour at Oroville Dam, California

10:40–11:00

David Cregger

Use of Wedge Analysis for Prediction of Rock Block Plucking Scour

11:00–11:20

Kimberly Davidson

Effects of Anchoring on Uplift, Bluestone Dam, Hinton, West Virgini2

11:20–11:40

Vanessa Bateman

An Analysis of Fully Grouting Vibrating Wire Piezometers Use at Center Hill Dam

11:40–12:00

Donald B. Riley

Rock Quality Characterization Using Blast Hole Penetration Rate Data USACE Isabella Lake Dam Safety Modification Project Kern County, California

Friday, September 18 – Afternoon

Hot Topics Panel (Sponsored By AEG Oregon Chapter) Moderators: Sarah Kalika and John Sager

The Walker Lane:

An Incipient Plate Boundary Dissecting the American West and Potential Heir to the San Andreas Fault 12:15 – 1:10 pm The 2019 Ridgecrest earthquakes in eastern California and 2020 Monte Cristo Range earthquake in western Nevada were a reminder that the Walker Lane (WL) is a fundamental part of the North American-Pacific plate boundary. Since ~30 Ma, western North America has evolved from an Andean-type margin to a dextral transform as marked by arc retreat, orogenic collapse, and inland steps of the San Andreas fault system. Inception of the WL in the late Miocene coincided with a change in relative plate motions, east shift of the southern part of the transform to the Gulf of California, and development of the Big Bend of the San Andreas. Dextral shear was favored in the WL, as it paralleled the new plate motion while aligning with the Gulf of California and bypassing both the convergent bottleneck of the Big Bend and relatively rigid Sierra Nevada block. The WL currently accommodates ~20% of the dextral plate motion (~10 mm/yr). In contrast to the continuous 1,100-km-long San Andreas fault, the WL is marked by shorter discontinuous faults. Progressive NW-younging in the onset of deformation (~10 to <4 Ma) and a general decrease in both length of and offset on dextral faults indicate NW propagation of the WL. The WL ends near the south end of the Cascade arc directly inboard of the Mendocino triple junction. Continued northward migration of the triple junction and NW-propagation of the WL suggest that they may eventually intersect off southern Oregon in ~7–8 m.y. The primary plate boundary may then step inland to the WL, similar to the late Miocene shift to the Gulf of California. Thus, the WL provides a superb natural laboratory for analyzing the initiation and progressive development of a major transform fault. Integrated analyses of the late Miocene to recent evolution, Quaternary faults, recent seismicity, and GPS geodetic data are critical for deciphering the progressive development, current earthquake hazards, and potential future evolution of this incipient plate boundary.

Speakers: James E. Faulds, Dr. Rich D. Koehler, and William C. Hammond James Faulds is the Nevada State Geologist, Director of the Nevada Bureau of Mines and Geology (NBMG), and professor at the University of Nevada, Reno (UNR). NBMG is a research and public service unit of UNR and is the state geological survey of Nevada. Faulds is a structural geologist with 30+ years of experience. He has been with UNR and NBMG since 1997, first as Professor and then serving as NBMG Director since 2012. He earned his BS at the University of Montana, MS at the University of Arizona, and PhD at the University of New Mexico. He has studied crustal deformation in many parts of the world, including much of the western US, western Turkey, and New Zealand. His research has focused on how fault systems initiate and evolve through time. In recent years, he has been analyzing the favorable structural settings and exploration strategies of geothermal systems in the western US, Turkey, New Zealand, and elsewhere. His geothermal journeys have included short-term appointments with the BRGM in France and both GNS Science and the University of Canterbury in New Zealand (as an Erskine Teaching Fellow) while on sabbaticals. He has published over 100 papers and dozens of geologic maps. He has also taught courses in structural geology, tectonics, geothermal exploration, and field geology, while serving as advisor for more than 25 graduate students.

September 2020 2018

AEG 61st AEG Annual 2020 Virtual Meeting/IAEG Annual Meeting XIII Congress – Program – Program with Abstracts with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING Dr. Rich D. Koehler is an earthquake geologist specialized in characterizing the timing and frequency of past earthquakes (paleoseismology) and the implications of this information for engineering geologic applications and seismic hazard assessments. He holds geology degrees from UC Santa Cruz (BA), Humboldt State University (MS), and University of Nevada, Reno (PhD). He is currently an Assistant Professor with the Nevada Bureau of Mines and Geology at the University of Nevada, Reno. Dr. Koehler has previously held positions in private consulting and state government including 6 years as the senior earthquake geologist for the State of Alaska. Dr. Koehler’s research has been conducted throughout the western US and internationally. He has also provided technical support for water storage dams, nuclear power plants, and multiple crude oil and natural gas pipelines.

William C. Hammond is a professor of geodesy and geophysics in the Nevada Bureau of Mines and Geology at the University of Nevada, Reno. His research involves using space geodesy to study active processes in the solid Earth. These processes include tectonic and seismic cycle deformation with application to hazards, mountain building, geophysical loading, tectonic controls on geothermal resources, mantle processes, and interactions between tectonic and magmatic systems.

Recently he has published academic research papers using GPS and InSAR to study vertical motion of Earth’s surface and its interaction with the climate system. He currently operates the MAGNET GPS network in the western Great Basin and eastern Sierra Nevada.

He currently serves on the National Academy of Science Board of Earth Science and Resources, and an NSF seismic and geodetic facility advisory committee. Recent past service includes chairing the NSF EarthScope Plate Boundary Observatory advisory committee, serving as secretary of the Geodesy Section of the American Geophysical Union, and as Associate Editor for the Bulletin of the Seismological Society of America. He is author or coauthor of ~100 articles, book chapters, maps, conference proceedings, guidebooks, and reports. He has earned degrees in applied mathematics and geophysics, and was a postdoctoral researcher at the US Geological Survey in Menlo Park, California.

Mount St. Helens 1:15–2:10pm Mount St. Helens, located in southwest Washington, erupted 40 years ago this year. Several engineering features were constructed to mitigate the immediate and long-term impacts from the eruption and subsequent debris avalanche, mud flow, and flooding. These features included stabilization of the Spirit Lake blockage, a gated outlet structure and tunnel to maintain a safe post-eruption lake level at Spirit Lake, and the Sediment Retention Structure (a sediment retaining earth dam on the North Fork of the Tuttle River). New studies are currently being performed to reassess the hazards that still exist to establish what actions may be necessary to maintain these existing projects and continue to protect the downstream communities. This work is being accomplished through cooperative joint efforts of the US Forest Service, the US Geological Survey, and the US Army Corps of Engineers. The three-person panel will discuss ongoing and planned work in the following areas: debris blockage characterization, a planned exploration program in 2021; geophysical surveys (seismic and GPR) of the eruption debris blockage at Spirit Lake; seismic hazard mapping; and, dam safety issues with respect to the blockage, and tunnel outlet.

Speakers: Jon Major, Rene’ Renteria, and Jeremy Britton Geologic, Geomorphic, and Hydrologic Context for Management of Spirit Lake – Jon Major is a research hydrologist with the US Geological Survey Cascades Volcano Observatory in Vancouver, Washington. He received his BS from University of Dayton, MS from Penn State, and PhD from the Department of Geological Sciences at the University of Washington. He has worked on groundwater flow in landslides, mechanics of deposition by debris flows, post-eruption sediment transport and streamflow hydrology, geomorphic responses to dam removals, and analyses of debris-flow and flood hazards at volcanoes in Washington, Oregon, Alaska, El Salvador, Chile, and the Philippines. He is a fellow of the Geological Society of America (GSA), and has received the GSA E.B. Burwell Award, the GSA Kirk Bryan Award, and a US Department of Interior Award for Excellence of Service.

Managing a Volcanic Debris Dam Geohazard Utilizing Dam Safety Principles – René Renteria, PE, Geotechnical & Dam Safety Program Engineer, USDA Forest Service, Pacific Northwest & Alaska Regions. Rentería has practiced geotechnical engineering for 35 years, with 25 years working for the USDA Forest Service, and 10 years involvement on the Spirit Lake project. René specializes in unstable slopes geologic modeling and geotechnical risk assessment. René obtained a dual degree BS in Civil and Forest Engineering from Oregon State University in 1985. He is a registered Professional Engineer in Oregon.

Spirit Lake Debris Blockage Explorations and Site Characterization – Jeremy Britton, Senior Geotechnical Engineer, Portland District, US Army Corps of Engineers. Britton has been with Portland District, USACE for 18 years, during which he has worked on several Mt. St. Helens related projects. He has a PhD from Virginia Tech in geotechnical engineering (2001) and is a registered Professional Engineer.

Jeremy Britton (right), drilling on the Spirit Lake debris blockage in the early 1980s

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AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 61ST ANNUAL AEG 2020 MEETING/IAEG VIRTUAL ANNUAL XIII CONGRESS MEETING

Poster Sessions (Sponsored By Mount Sopris Instrument Company, Inc.) All poster presentations will be pre-recorded (no live presentations) for the AEG 2020 Virtual Annual Meeting.

We will have a link for each presenter, with their abstract, bio and video presentation.

Vote for Your Favorite Poster! – Student Poster Competition All AEG 2020 Virtual Annual Meeting attendees will be viewing the videos and voting for their favorite.

Prizes will be awarded for First Place ($250), Second Place ($150), Third Place ($75), and Fourth Place ($25) based on the attendee’s votes.

The winners will be announced on Friday, September 18, 2020 at 2:00pm following the AEG Foundation Awards.

Speaker

Title

Jeng Hann Chong

Estimating Sediment Discharge at a Sediment-Filled Dam in Malibu Creek Using Digital Elevation Models (DEM)

Joseph Cook

Landslide Mapping along the I-17 Corridor, Central Arizona

Brittany Coupe

The Influence of Deep-Seated Slope Failures on the Evolution of the Cretaceous Hogback Encircling the Black Hills, South Dakota

Megan Doughty

Mapping Increases in Hyporheic Exchange from Channel-Spanning Logjams

Sarah Harris

Residential Property Annual Slope Movement Monitoring in Erwin, Tennessee

Emma Heavener

GPR Investigation of Mine Subsidence Hazards in Charlotte, North Carolina

Joel Hirales-Rochin

Analysis of Geohydrological Risks based on SR & GIS from the Southeast Portion of the City of La Paz, Baja California Sur, Mexico

Catherine Hobart

Dog Valley Fault as a Potential Threat to Stampede, Prosser Creek, and Boca Dams

Ana Maria Carmen Ilie

Are Low-Cost Monitors Good Enough to Help People Understand Poor Air Quality in Their Neighborhood?

Jeffrey Keaton

When Can Four–Twelve Tests Be Sufficient for Engineering Design Parameters? A Tale of Two Papers

Kara Kingen

Climatic Controls on the Kinematics of the Hooskanaden Landslide, Curry County, Oregon

John Louie

Database of Geotechnical Shear-Wave Seismic-Velocity Profile Measurements for California and Nevada

Justin Manning

Geologic Hazard Mapping of Mining Communities in Peru using Remote Sensing and GIS

Ozotta Ogochukwu

Change of Bakken Shale Stiffness due to CO2 Saturation

Thomas O’Shea

Investigating Risks Related to Unstable Slopes in Great Smoky Mountains National Park

Isaac Pope

Poorly Sorted Terrace Deposits of the Cispus Valley: Glacial Drift or Mount Adams Lahar?

Carson Reimers

Use of Close-range Photogrammetry to Generate 3D Models of Drill Core

Emily Smoot

An Investigation and Comparison of Stable Isotopes in Meteoric Waters and Groundwaters from Southern Washington

Steven Terracina

Use of Synthetic Aperture Radar for Detecting Subsidence Features in the Lower Mississippi River Valley

Leon van Paassen

Interactive Games for Teaching Site Investigation and Engineering Geology

Index to Advertisers Advertiser Bryan Environmental Gannett Fleming

On the Cover…

Page 6 Inside Front Cover

Landslide Technology

52

Mount Sopris

14

Pali Consulting

25

PBS

58

Princeton Geoscience

9

Schnabel Engineering

17

UPenn September 2018

Back Cover

News

Vol. 63, No. 4 – Program with w Abstracts

Cover captions, clockwise from top left: Images from our two Hot Topics sessions: Aerial view of Spirit Lake (center) looking north from above the crater of Mount St. Helens Mount St. Helens and North Fork Toutle River Channel

AEG2020

Virtuual Confereence

Program m with Abstraaacts cts

AEG 61st Annual Meeting/IAEG XIII Congress – Program with Abstracts

Nevada State Geologist James Faulds leading field trip to the fault scarp of the Walker Lane Walker Lane Pyramid

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AEG 2020 VIRTUAL ANNUAL MEETING

Abstracts Lessons Learnt from the Use of Google Earth/ Google Street View for Rockfall Hazard Rating

Post-Eruption Transportation Repairs at Hawai’ian Volcanoes National Park

Admassu, Yonathan, Department of Geology and Environmental Science, James Madison University, admassyx@jmu.edu (TS #6)

Arthurs, James, Central Federal Lands Highway Division, Federal Highway Administration, james.arthurs@dot.gov (TS #4)

Rockfalls are common types of slope failures that are hazardous to motorists and cause damage to roadways. Rockfalls are commonly a result of unfavorable orientation of discontinuities and presence of undercut rock layers. One of the most common approaches to deal with rockfall hazard is the use of the rockfall hazard rating systems (RHRS) which is a semi-quantitative method of characterizing rock slopes’ risk to generating rockfalls and consequence of rockfall events. The risk of rock slopes to generate rockfalls is controlled mainly by the prevalent geological attributes such as discontinuity characteristics, whereas the consequence of rockfall events is dependent on the height of the slope, presence of rockfall catchment ditch, sight distance and so on. The RHRS gives scores to individual risk and consequence factors. The overall RHRS rating is a sum of individual scores. Determination of risk and consequence factors is traditionally accomplished through field visits. The field visits include driving to the rock slope and hours of data collection at the site making it an expensive undertaking. Remote sensing methods such as Google Earth in conjunction with Google Street View have shown promise as time saving and much less costly methods for RHRS determination (Swanger and Admassu, 2019). At selected sites in western parts of Virginia, the results of Google Earth/Google Street View-based RHRS method was cross-checked against field-based RHRS determination. The success of the Google Earth/Google Street View method were evaluated based on 1) its ability to locate slope cuts and 2) accuracy of measurements for RHRS factors.

The May 2018 eruption of Kilauea volcano caused significant damage to roadways and trails in the Hawai’ian Volcanoes National Park.

Ground deformation during the eruption caused surface displacement on known fault systems as well as development of fissures and cavities in other areas. Prior to the eruption, the Central Federal Lands Highway Division performed seismic refraction surveys to identify the extent of subsurface cavities in areas with poor pavement performance. After the eruption, surficial site reconnaissance was conducted to identify additional areas of damage, develop repair recommendations, and prepare and administer a repair contract on behalf of the National Park. Due to limited available information on dimensions of the fissures and cavities, the repair plans provided typical treatments with the intention to adapt the repair in the field. Repairs typically consisted of large rock to choke fissures, smaller rock to fill to the pavement subgrade elevation, and a single layer of geotextile filter fabric and biaxial geogrid to support the pavement section. Repair work was started in February 2020 and largely completed in April 2020.

Historic Analysis and Future Expansion of the EisenhowerJohnson Memorial Tunnels, Part 2: Geotechnical Analysis Alexander, Gauen, Colorado School of Mines, galexander@mines.edu; Ashton Krajnovich, akrajnov@mines.edu; Marte Gutierrez, mgutierr@mines.edu; Stephen Harelson, stephen.harelson@state.co.us (TS #1) The Eisenhower-Johnson Memorial Tunnel (EJMT) is a pair of two-lane vehicular tunnels carrying Interstate 70 under the continental divide in Colorado. The original construction encountered highly variable geologic conditions from massive intact granite to squeezing fault gouge.

Ongoing research is informing the future expansion of the EJMT and focuses on two parts: geologic modeling and geotechnical analysis.

The primary focus of the geotechnical analysis is to develop probabilistic rock mass classifications based on as-built data in the pilot bore and Eisenhower bore of the existing tunnel. The rock mass classifications are validated by back-analysis to installed supports and measured deformations and loads. The validated probabilistic rock mass classifications are then input to the structural geologic model as uncertain and spatially variable parameters. The structural geologic model, including stochastic rock mass classifications, is then sampled along the alignment of proposed additional bores adjacent to the existing EJMT. Distributions of rock mass classification parameters along the proposed alignment are created. Iteration of alignments can then be used to search for the most favorable geologic conditions.

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Alaska Radon Testing and Occurrence: Now That We Know Better, We Are Working To Do Better Athey, Jennifer E., Alaska Division of Geological & Geophysical Surveys, jennifer.athey@alaska.gov; Art L. Nash, alnashjr@alaska.edu; Leif E. Albertson, Jr., leifalbertson@gmail.com; DeShana D. York, ddyork@alaska.edu (TS #2) The US Environmental Protection Agency (EPA) and US Geological Survey cooperatively published radon data for EPA Region 10 in 1993, which included a predictive analysis of radon in Alaska based on the data and data synthesis techniques available at the time. The resulting radon map of Alaska, produced more than a quarter of a century ago, persists online and is still the primary Alaska radon map indexed by the Google Images search tool for public consumption today. The map indicates a low to moderate radon concern for the entire state, which anecdotal evidence suggests has unintentionally led to an Alaska public that is largely unaware of the existence of radon and its hazard to human health. Furthermore, lack of public concern and sparse and undocumented statewide radon testing has created little demand for and subsequent availability of local, certified mitigation and testing service providers. The Alaska Division of Geological & Geophysical Surveys and University of Alaska Fairbanks’ Cooperative Extension Service have recently made significant inroads toward better understanding the radon potential in the state. A new predictive radon map indicates multiple areas of radon concentration averaging four picocuries per liter or greater, although testing data are still sparse in many locations. Sharing this information with the public is not only increasing public awareness of the hazards of radon, but also homeowner-initiated testing and mitigation. In this presentation, we will discuss the new radon-predictive map for Alaska (https://maps.dggs.alaska.gov/radon/), our strategies for increasing testing and mitigation in urban and rural areas of the state, and social behaviors we have witnessed as a result of the map-based outreach and increased media attention on radon.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING New Abstract:An Overview of Analytical Test Methods for NOA Bailey, Mark, Asbestos TEM Labs, mark@asbestostemlabs.com Selecting analytical protocols when assessing the presence and concentration of asbestos occurring naturally in rock and soils, generally called naturally occurring asbestos or NOA, is a challenging task and not one with a one-size-fits-all approach. Choices commonly need to be made regarding: a) the choice of sample type submitted (focused, composite, or multi-increment), b) the disaggregation method used (crushing and pulverizing) including type of crusher & grinder (jaw crusher, disc pulverizer, hammer mill, ring/puck shatter box, ball mill, etc.) to be used, or the employ seives to separate fines, c) the type of analysis method to be run (PLM or TEM, qualitative or quantitative), d) the fiber dimensions used discriminate between fibers countable as asbestos and non-countable particles of the same minerals with lower aspect ratios, e) the minerals beyond the regulated six asbestos minerals, if any, to be counted [i.e. winchite/richterite, glaucophane, hornblende, erionite, antigorite, …], f) stopping rules for high NOA concentration samples to minimize sample analysis time & expense, g) if weight percent and/or fibers per gram are to be calculated and reported, h) whether photomicrographs or EDX spectra are to be included, and more. A discussion of the use of SEM, thin section petrography and XRD are also discussed. Additionally, an approach is recommended whereby both the identified rock type and the other minerals found coexisting with identified suspect fibers are used to confirm the mineral species of the suspect fibers. Cases studies of the use of these various methods in situations where fibrous minerals, both NOA and non-NOA, were found will be described.

Dam Failures in Hindsight. Lessons Learned?

Balven, Matthew, Gannett Fleming, Inc., mbalven@gfnet.com (TS #5) Dam failures and significant dam safety incidents are relatively rare, but they do occur, and several notable ones have occurred in the past decade. This paper discusses how good meaning study of these events and effort to prevent the reoccurrence of these memorable types of dam failures may result in over prediction (availability bias) of these events reoccurring. Additionally, availability bias along with limited information on design as well as operation and modification records, can lead to other unrelated but viable potential failure modes being overlooked. This bias limits our ability to fully characterize risks. Uncertainty and biases impact our ability to comprehensively assess dams for potential failures. Some examples from recent safety assessments are provided. We compare the frequency of certain failure modes in when evaluating potential failure modes (PFMs) for a dam immediately following recent dam safety incidents; such as, Taum Sauk, Wanapum, and Oroville. The frequency of the PFMs following the events are compared to the frequency of similar PFMs postulated in dam safety workshops conducted prior to the dam safety incidents. This paper will look at ways to manage an overrepresentation of these recent failures that are readily available to the mind during the dam safety assessment process. Specific examples used to overcome bias are provided, including: nominal group technique, multiple expert elicitation, fact-based analysis, and decomposition of scenarios.

September 2020

Towards a Model for the Permanent Eradication of Mine Related Asbestos Pollution in South Africa Barker, Oliver, Banzi Geotechnics, obb@banzi.co.za (TS #3) Naturally occurring asbestos minerals (NOAMs) are endemic in many regions of South Africa. This is due to the abundance of serpentine that occurs in the Archaean basement rocks of South Africa. In addition, NOAMS are widely developed in our Proterozoic sequences such as the Transvaal Supergroup. These rock sequences are developed in extensive swathes through the northeastern regions of SA as well as the northern Cape Province. NOAMS are even present within the boundaries of the Cradle of Humankind north of Johannesburg.

The need for a solution of the post mining NOAM pollution problem in South Africa vies in importance with that of AIDS, TB and now Covid 2.

Asbestosis and related forms of illness are arguably among the most pernicious chronic diseases known to man. The eradication of asbestos pollution is, unlike the AIDS virus, technically feasible given present knowledge and capabilities. The major ingredients that have been missing so far have been political will, commitment and money.

The paper reviews current rehabilitation practices in South Africa and shows that these are unsustainable over the long term. The paper provides suggestions as to the path that needs to be taken if a sustainable solution is to be found. The scientific and engineering professions, the SA Government and to the world at large are challenged to address this scourge through broad, comprehensive actions not contemplated to date. The future health of thousands of South Africans and many international visitors to our country depends on finding a sustainable solution.

An Analysis of Fully Grouting Vibrating Wire Piezometers Use at Center Hill Dam (2012–2020) Bateman, Vanessa, US Army Corps of Engineers, vanessa.c.bateman@usace.army.mil (TS #8) Industry has recommended the use of Fully Grouted Vibrating Wire Piezometers (FGVWP) as a replacement for open standpipe and nested piezometers for many applications. However, despite many years of use, there remains controversy in the accuracy of these instruments use in comparison with open standpipe and nested piezometers using a screened interval. Discussions have often centered in the reliability of these instruments, in controversy over responsiveness of the instruments, how closely vibrating wire piezometers can be spaced in a nested borehole installation and in the effectiveness of transmission of grout pressures through different grout mixes to the vibrating wire piezometer sensor. Center Hill Dam, however, is an excellent test case for a comparative evaluation of these FGVWP installations with conventional installations as there have been over 96 FGVWP sensors installed in a variety of materials (embankment, alluvium, different geological layers of rock) alongside conventional piezometers (more than 150 measured locations) and these FGVWP have been in use on the project since 2012. Conventional piezometers have been in continuous use on the project since the 1970s. Additionally, many manually read piezometers on the site were automated by putting a vibrating wire sensor into a conventional borehole. This allows for an “apples to apples” comparison of the readings as they were both read on the same reading frequency with an automated monitoring system. This eight-year span allows for a unique view into the potential effectiveness, reliability and challenges of using these instruments both during construction of a cutoff wall (2012–2014) and for the monitoring period after construction has ended.

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AEG 2020 VIRTUAL ANNUAL MEETING Landslide Features on the WNC Blue Ridge Escarpment - It’s a Complex Issue Bauer, Jennifer, Appalachian Landslide Consultants, PLLC, jennifer@appalachianlandslide.com; Stephen Fuemmeler, stephen@appalachianlandslide.com; Phil Prince, philip@appalachianlandslide.com, Rebecca Latham, rebecca@appalachianlandslide.com, Aras Mann, aras@appalachianlandslide.com (TS #6) Through the re-instated North Carolina Geological Survey Landslide Mapping Program, landslide mapping has begun in Polk and Rutherford Counties along the Blue Ridge Escarpment (BRE) in the southern portion of Western NC. The steep slopes of the BRE separate the mountains from the piedmont physiographic provinces. These steep slopes, along with variable lithologies ranging from amphibolite to granitic gneiss, relatively flat-lying foliations, and thin to thick bedrock weathering profiles have led to an abundance of slope movement mechanisms and material types. Use of the hillshades, slope raster, and slopeshade derived from QL1 high-resolution (processed to 0.5m DEM) lidar have been especially useful in identifying features for field verification, defining feature boundaries, and determining relative ages.

This high-resolution lidar has changed the mapping process, leading to more confidence in the features that are included in the landslide inventory in the heavily vegetated landscape. Appalachian Landslide Consultants, PLLC, has contracted with the NCGS and has identified slope movement processes ranging from recent debris flows and active debris and weathered rock slides, large rock falls of unknown age, and dormant—historic to dormant—mature debris and weathered rock slides. Slope movement features made up of a variety of different types of slope movements and deposits are mapped as “slope movement complexes” in order to distinguish them from accumulations of slope movement deposits. Many of these slope movement complexes and dormant deep-seated slides have been reactivated and have evidence of historic and active movement. Mapping these features is important for understanding how modification of these features may trigger instability, thereby impacting public safety and property.

Finding the American Tunnel: Using Directional Drilling Techniques to Intersect Abandoned Mine Workings Beckman, E. Morley, Deere & Ault Consultants, morley.beckman@deereault.com; Erinn Johnson, erinn.johnson@deereault.com; Christoph Goss, christoph.goss@deereault.com; Kerry Guy, guy.kerry@epa.gov; Rob Burton, r.burton@erllc.com (TS #4) This presentation provides an overview and technical details regarding the use of both conventional coring and directional drilling techniques, paired with good old-fashioned historical research and geometry, to successfully install a monitoring well into an abandoned mine tunnel.

During the summer of 2019, a joint team of geologists, engineers and specialty drilling contractors worked for the EPA at the Bonita Peak Mining District Superfund Site near Silverton, Colorado. The team successfully installed a monitoring well in an inclined borehole drilled into the American Tunnel. Through a combination of historical research, careful digitization of hand-drawn maps from the 1970s, detailed ground survey, gyroscopic and magnetic surveys within the borehole, and directional drilling techniques, the team was able to intercept the suspected location of the 11-foot-diameter tunnel from over 600 feet away. The drilling was completed through intensely fractured, altered and faulted andesitic rock. Conventional geotechnical drilling methods can result in significant “wandering” of the borehole (by up to five degrees or more) due to deflection of the drill stem within the rock.

The introduction of a steerable drill bit allowed for careful correction of the borehole as it progressed. The program was ultimately successful, 32

allowing for construction of a monitoring well into a sealed portion of the American Tunnel. This well will provide water level and water quality data to augment our understanding of hydrology in the region and the hydrologic impact of myriad abandoned mine workings in the area.

Addressing Geologic Hazards in the Newell Creek Canyon Natural Area through Avoidance, Accommodation, and Mitigation Blackwood, Timothy, Pali Consulting, Inc., tim@pali-consulting.com; Jack Powell, jack@pali-consulting.com; Rod Wojtanik, Rod.Wojtanik@oregonmetro.gov (TS #4) Metro, a regional government in the Portland, Oregon, metropolitan area, acquires natural areas in the region to protect water quality and preserve wildlife habitat. Metro develops some natural areas to provide connections to nature and provide passive recreational opportunities to area residents. The Newell Creek Natural Area is one of Metro’s newest natural areas under development. Located within the headwaters of Newell Creek Canyon, the area is known for its rugged character and associated geologic hazards. Understanding the challenges of developing such terrain, Metro commissioned a geotechnical assessment of the project early on, at the land use planning stage.

The geotechnical assessment identified several hazards, including deep-seated landslide movement, rockfall occurrence, and possible debris flow paths. The hazards had potentially significant effects on development of the natural area in terms of public safety, user experience, and cost. Avoiding all hazards would have severely restricted areas that could be enjoyed by the public. Conversely, mitigating all hazards would far exceed available funds to develop the natural area.

Working with a multi-discipline design and a construction team, Metro adopted a strategy of avoiding, accommodating, and mitigating hazards to optimize safety and accessibility while meeting the project budget. This paper discusses how these strategies were applied to avoid hazards (locate paths and a day use area), accommodate hazards (design for differential displacement of bridge abutments), and mitigate hazards (stabilize a rock outcrop) where the hazards could not be avoided or accommodated. Insights are provided into selection of the appropriate strategies as well as the technical details required to make the decisions and design project elements at risk.

Current Status of Risk-Informed Decision Making for Dam and Levee Safety Programs Boyer, Douglas, Federal Energy Regulatory Commission, douglas.boyer@ferc.gov (TS #5) The state of the practice for dam and levee safety evaluations has been slowly evolving over the past decade or so. Traditionally, dam and levee safety evaluations have been based on deterministic design standards and guidelines. More recent dam and levee safety evaluations have included the use of potential failure mode analysis (PFMA) as a tool to help identify the possible ways a dam or levee could fail.

After many years of successful use by the Bureau of Reclamation and US Army Corps of Engineers, other Federal agencies and the general dam and levee safety industry is now moving towards embracing riskinformed decision making. This approach builds on the PFMA process by using probabilistic approaches in estimating the likelihood of failure and consequences. Many other industries have been using risk approaches for years to evaluate safety concerns, including NASA, Federal Aviation Administration, Federal Highway Administration, Food and Drug Administration, the petrochemical industry, and the nuclear industry, to name just a few. This shift to incorporating risk principles and concepts will require all those involved in the dam and levee safety industry to expand their knowledge and approach in using risk concepts and principles. It will take some time for the industry to develop

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AEG 2020 VIRTUAL ANNUAL MEETING and apply these skills, but it will be beneficial to all, including those using the results from this approach to make better-informed decisions and to the public in knowing the risks posed by dams and levees are being properly managed and addressed. This presentation will discuss the evolution of risk-informed decision-making, advantages and disadvantages, limitations, sources of available resources and guidance, and where the industry is headed.

Unlined Spillway Erosion, Contributions from Hillside Channel Flow and Local Impinging Jet Scour at Oroville Dam, California Briggs, Stephanie M., Lettis Consultants International, Briggs briggs@lettisci.com; Michael George, mgeorge@bgcengineering.ca; Christopher Kissick, ckissick@geiconsultants.com; Sarah Smith, smith@lettisci.com; Hans AbramsonWard, abramsonward@lettisci.com, Holly J. Nichols, Holly.Nichols@water.ca.gov (TS #8) Scour of rock and soil from unlined spillways during spill events can cause a range of unintended environmental, safety, and reliability consequences for hydropower infrastructure sites. In February 2017, headcutting erosion in the Oroville Emergency Spillway prompted the evacuation of nearly 200,000 downstream residents. In response to this incident, and in order to protect against future erosion, DWR installed a roller compacted concrete (RCC) apron and a secant pile wall (SPW) in the emergency spillway. After installing this protection, DWR conducted a comprehensive risk-based needs assessment of the Oroville Dam facilities to identify opportunities to improve the reliability, redundancy and resiliency of the emergency spillway and other facilities. This presentation will describe the screening-level, site-specific study DWR conducted to evaluate potential erosion in the emergency spillway as part of this review. The study evaluated contribution to erosion from two primary sources: (1) hillside channel flow erosion, and (2) local scour from an impinging jet directly downstream of the SPW. There currently is no model available that can adequately quantify scour from these two conditions simultaneously; and thus, estimates of material removed by both processes were modeled independently, then summed for total erosion values. For the hillside channel flow, an iterative analysis used stream power calculated from HEC-RAS software from the US Army Corps of Engineers. For the local scour, the flow erosive capacity was calculated analytically for an impinging jet.

At low discharges, the primary source of erosion is hillside channel flow. However, for storms larger than the 5,000 year event (with approximately 211,000 cfs routed through the emergency spillway) and up to the probable maximum flood (approximately 422,000 cfs), the local impinging jet removes more material. The resultant estimated volumes of eroded material were used to assess the impacts of sedimentation in the diversion pool downstream.

Assessment of 14 TVA Spillways and the Evaluation of Erodibility for Earth Cut Spillways Burch, Scott, Gannett Fleming, sburch@gfnet.com; Scott Walker, srwalker3@tva.gov; William Kingston, wkingston@gfnet.com; Paul Schweiger, pschweiger@gfnet.com; Vladimir Cecka, vcecka@gfnet.com (TS #8) In 2019, the Tennessee Valley Authority (TVA), with assistance from Gannett Fleming (GF), conducted the second phase of a comprehensive evaluation of primary and emergency spillways at 14 TVA dams located in Tennessee, North Carolina, and Virginia. This phase focused primarily on unlined spillways. Before starting the field assessments, a comprehensive data review was conducted for all spillways including design and construction information, foundation conditions, documentation from previous inspections, and relevant instrumentation data.

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Following this review, each spillway was inspected and assessed by the authors. Overall, the spillways were found to be in good condition and well maintained. Based on historical data and field assessments of the earth cut spillways, spillway erodibility (stability and integrity) analyses for select emergency spillways were performed using the SITES computer program developed by the Natural Resources Conservation Service (NRCS). Once the erodibility analyses were complete, GF conducted a qualitative Potential Failure Mode Analysis (PFMA) for each spillway. The results of the PFMAs indicate that the overall condition of the spillways was very good. However, the earth-cut spillways, despite being designed in accordance with the proper design criteria at the time and being well maintained, were subject to potential erosion and headcutting under extreme, low-probability flood events. For many of the earth-cut spillways, this Potential Failure Mode (PFM) would likely result in extensive damage to the spillway. However, there were a few spillways where this PFM could result in significant downstream impacts. Based on GF’s assessment, TVA gained a better understanding of how these spillways may perform during extreme loading conditions. TVA has recently initiated the next phase of investigation and evaluation of selected unlined spillways. Going forward, results and recommendations will be incorporated into TVA’s dam safety risk program, which is used to prioritize activities and actions across TVA’s entire river dam portfolio.

Radon-The Invisible Geological Killer—Geologic Characteristics that Lead to High Radon Production Burns, Scott, Professor Emeritus of Engineering Geology, Portland State University, Portland, Oregon; Past President, IAEG (International Association for Engineering Geology and the Environment), burnss@pdx.edu (TS #2) Radon is a natural, invisible, odorless, and tasteless gas that is emitted from the subsurface all over the world. It gets trapped in homes due to efforts to conserve heat. The EPA now estimates that this radioactive gas causes 20% of all of the lung cancer deaths in North America. Professor Scott Burns has led a team of students at Portland State University studying this problem for 30 years. This talk will discuss how radon gas is formed, testing methods, and—if the levels are high—how radon can be mitigated. Radon testing is easy and it is inexpensive to mitigate; no one needs to be dying from it! The factors that affect the amount of radon in a home include the geology under the house, the soil permeability, the groundwater, and the construction of the house itself. Geological characteristics that can lead to high radon production include certain types of rocks, such as granite, phosphatic rocks and dark shales, and certain types of earth movement, such as landslides and faults. Short and long term tests are used to determine the levels of radon present in the indoor air in a home. The EPA currently recommends a radon “action level” of 4.0 picocuries/liter, above which the air in the home should be mitigated.

An early, user-friendly, mapping approach to display radon risk to homeowners, developed at Portland State will be presented. Dr. Burns will explain how the data were collected and how they were converted into a readily understandable classification of low, moderate and high potential for radon—-based on zip code. This system made it easy for nontechnical people to understand radon risk. In Portland’s 76 zip codes, 16 were found to have a high risk, 42 moderate and 18 were found to have low potential for radon impact. This zip code study has been expanded for use throughout the state. Dr. Burns will explain how outreach has worked in Oregon, using this approach to educate people about radon.

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AEG 2020 VIRTUAL ANNUAL MEETING Improving Satellite-Based Precipitation Using Rain Gauge Observations for Landslide Prediction in a Data Sparse Region Chakrapani Lekha, Vishnu, Michigan Technological University, vchakrap@mtu.edu; Thomas Oommen, toommen@mtu.edu; Sajinkumar K S, skochapp@mtu.edu; Snehamoy Chatterjee, schatte1@mtu.edu (TS #6) Rain-triggered, shallow landslides constitute a significant problem in many parts of the world. A landslide nowcasting model that could predict landslides based on precipitation values could be efficient in saving lives and reducing risk. However, areas like Idukki, Kerala, with a sparse rain gauge network, call for the use of satellite-based rainfall products (e.g., Global Precipitation Measurement (GPM). However, the GPM research-ready product is available at a latency of 3.5 months and is thus not applicable for near-real-time landslide predictions.

Therefore, in this study, we have made a comparison of the near realtime GPM data with 14-hour latency and the research ready product with the rain gauge values in Idukki for June, the beginning of the monsoon season, for the year 2018. It was found that both the near realtime and final data products had comparatively less correlation with the ground truth data, with the near real-time data having slightly better (0.45) than the research-ready product (0.42). However, this is fairly low accuracy to work with, and the GPM data had to be calibrated (to local conditions?). A conditional merging algorithm was used to improve the accuracy of the GPM values. For this method, the GPM values corresponding to the rain gauge location were used to create a kriging field (KRg). This field was subtracted from the actual GPM raster (R) to get an error field (R-KRg). Another Kriging field with the actual rain gauge observations as values were created (Kg) and added with the error field. The resulting Conditional Merged product was found to have a correlation of 0.86 with the actual rain gauge values.

Thus, conditional merging provides a highly accurate GPM data product with a better temporal resolution than the final research-ready product and can be readily available for developing for near-real-time landslide predictions.

Estimating Sediment Discharge at a Sediment-Filled Dam in Malibu Creek using Digital Elevation Models (DEM) Chong, Jeng Hann, California State University Northridge, jenghann.chong.43@my.csun.edu; Adit Ghosh, adit.ghosh.605@my.csun.edu; Scott Hauswirth, scott.hauswirth@csun.edu (Poster) The 100-ft Rindge Dam situated along the Malibu Creek in Southern California is completely sediment-filled. A previous study indicated that the dam was filled with sediment within 34 years. Due to the environmental impact of the dam, there is an ongoing discussion regarding its removal. However, there are also arguments opposing the dam removal, including the potential for unfavorable downstream sediment transport and debris flows. Furthermore, there is limited sediment load data with only one gauging station in the watershed, ~3 km upstream of the dam. In this study, we use 1meter-DEM obtained from a lidar survey to estimate the sediment load along Malibu Creek that resulted in sedimentation of the reservoir and the potential effects of the possible future removal of the dam. We obtain the DEM of different cross-sectional profiles along the river using QGIS and automate the extraction of parameters, including slope, wetted perimeter, cross-sectional area, and discharge using MATLAB. We assume a constant discharge along the river to get the velocity and water stage at individual cross-sectional profiles to calculate the sediment discharge. We also compare with in-situ measurements of other rivers to determine the reliability of this method. Overall, we show that our method can be applied to other river basins with similar 34

climate and water properties, which lack field data measurements.

Landslide Mapping Along the I-17 Corridor, Central Arizona Cook, Joseph P., Arizona Geological Survey, joecook@arizona.edu; Brian F. Gootee, bgootee@arizona.edu (Poster) Landslides occur in a variety of landscapes and geologic settings throughout Arizona. Prior to 2015, our knowledge of the number and distribution of these slides was limited and scattered across many geologic maps and reports. In 2015 the Arizona Geological Survey (AZGS) compiled the Arizona Statewide Landslide Inventory Database (AzSLID) which included all known mapped and published landslide deposits throughout Arizona. Many additional, previously unmapped landslides were identified in aerial imagery and topographic data during this process. These interpreted features were included in AzSLID but no field verification was conducted. All landslide mapping is available for viewing and download on the AZGS Hazard Viewer online.

In 2019, AZGS began a new project to study the character and extent of landslide deposits along I-17 from Anthem to Flagstaff, using a combination of field mapping with high-resolution topography. This study area was chosen because of the potential high impact landslides may have on existing infrastructure as well as upcoming plans to expand I-17 near Black Canyon City; an area with many mapped landslides.

Damage to roadways by landslides can be catastrophic and extremely expensive to repair and mitigate. In 2008, a section of AZ State Route 87 was damaged by a reactivated portion of a larger slide cut by the road. In 2013, a similar failure within the Bittersprings landslide resulted in the destruction of a portion of US 89. Assessment, repair, and reroutes associated with these events totaled $18M, and $60M, respectively. The results of this study include verification of interpreted AzSLID landslides, more detailed mapping, description of the extent of known landslide deposits within the study area, and the discovery of additional previously unknown landslide deposits. These improvements to our knowledge of landslides in high-impact areas along I-17 will be useful for planning and hazard assessment.

Tunneling Group – Keynote Cording, Ed, Professor Emeritus of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign, cordingconsult@gmail.com (TS #1) As noted by Dr. Ralph Peck, one of the most powerful tools we possess as engineering geologists and geotechnical engineers is our observational skills. For underground construction design, the observation of the ground conditions and ground behavior and our ability to convey this information to the tunnel designers is often more important than the actual classification of the rock or ground type. During construction, an understanding of the geotechnical instrumentation data combined with an understanding of the ground behavior and the ongoing construction activities serve as an early warning system that helps to anticipate and resolve potential problems. As tunnels become larger in diameter using advanced technology in ever more challenging ground conditions or locations, these observational skills become increasingly more important. Dr. Cording will present a two-part talk about his experiences and the importance of observation from numerous projects, including the Washington DC Metro and Seattle’s Alaska Way projects.

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AEG 2020 VIRTUAL ANNUAL MEETING The Influence of Deep-Seated Slope Failures on the Evolution of the Cretaceous Hogback Encircling the Black Hills, South Dakota Coupe, Brittany, South Dakota School of Mines and Technology, Brittany.coupe@mines.sdsmt.edu; Kurt Katzenstein, Kurt.Katzenstein@sdsmt.edu (Poster) This ongoing study investigates the role played by deep-seated slope failures on the evolution of the Cretaceous hogback ridge encircling the Black Hills in South Dakota. Of particular interest is the role played by the thickness of exposed shale units in the lower portion of the hogback on stability and the resulting evolution of the hogback. Several hogback slopes exposed on the east side of the Black Hills have been characterized geotechnically and evaluated to determine how existing and more extreme hypothetical geologic/geotechnical conditions affect the global stability of the ridge. Also assessed is the difference in modeled stability on similar profiles using both 10-meter and new 1-meter DEM data to generate slope profiles.

Use of Wedge Analysis for Prediction of Rock Block Plucking Scour Cregger, David, AECOM, david.cregger@aecom.com (TS #8) Kinematic stability of rock blocks subject to scour is predicted by use of lower hemisphere stereonet projections, which is a standard technique in structural geology. In sedimentary rock, the low angle bedding plane separations are often dominant to the overall fracturing of the rock mass. Geologic mapping of spillways and river channels during dry season can provide the necessary orientations of the other joint sets typically somewhat vertical that may not be detected in vertical test borings. Intersections of three planes can produce rock blocks which must be further oriented with respect to flow direction to determine the relative ground structure number for use in empirical erodibility index. Discontinuity planes intersect along a plunge angle and azimuth. Kinematic rules typically require this line of intersection to daylight in the face of the rock exposure. One plane, for example bedding, may take more weight than the other and in presence of water pressure may be uplifted and detached resulting in plucking. Rock slope 3D analysis is used assigning angle of internal friction and cohesion of each interface to determine factor of safety, which is dependent on depth of the potential wedge. Statistically, these orientations are determined on the stereonet from geologic mapping and frictional properties determined from laboratory tests reduced to appropriate values for the rock mass. Application of the stream power and orientation is then completed for the depth of scour.

“From Scoured to Safety” – Rehabilitation of Lake Roland Water Supply Dam, Baltimore, Maryland Dalal, Visty, Maryland Dam Safety Program, Visty.dalal@maryland.gov (TS #5) Lake Roland Dam, a concrete/masonry gravity dam, was built in 1861 approximately 0.6 miles north of Baltimore. The lake impounded by the dam was the city’s first effort to establish a citywide water supply system and one of the two sites across the country used for largescale testing of water purification on a public water system through the addition of liquid chlorine. In 1915, the dam and lake were converted as a park and recreational facility for the City and Baltimore County. The three tributaries—Jones Fall, Roland Run, and Towson Run—that drain an area of about 40 square miles caused a severe siltation problem as the watershed became heavily urbanized. The ‘Phase I’ inspection and evaluation of the dam conducted by the US Army Corps of Engineers in March 1979, graded the dam as “high hazard” and classified it as “unsafe, non-emergency” due to the spillway capacity of 10% of the PMF and predicted failure at a disSeptember 2020

charge of 35% of PMF. Two tropical storms—Agnes in June 1972, and David in September 1979—had produced a 36% discharge of the PMF with the resultant flooding causing near failure conditions by eroding the earth and rubble fill on the downstream side of the abutment.

These conditions brought about the dam’s structural integrity concerns. The City of Baltimore conducted Phase II investigation that similarly concluded that there were structural integrity problems with the spillway and gatehouse and the spillway was capable of passing 13% of the PMF without overtopping. The City of Baltimore’s Department of Recreation and Parks, decided to rehabilitate the dam and provide additional spillway capacity. The design included architectural, mechanical, structural and hydraulic improvements to achieve a functional design that was aesthetically similar to the original structure.

Effects of Anchoring on Uplift, Bluestone Dam, Hinton, West Virginia Davidson, Kimberly, US Army Corps of Engineers, kimberly.d.davidson@usace.army.mil (TS #8) Bluestone Dam, completed in 1948, is a 2,065-ft-long, 165-ft-high concrete gravity structure on the New River in southern West Virginia.

Its primary purpose is flood control, and it sits mostly empty during normal conditions. During inspection of the dam in the 1960s, potential stability issues were identified related to faulting that had been discovered during construction but never fully assessed. In addition, updated hydrologic analysis shows that the dam would be overtopped by the Probable Maximum Flood. Site and laboratory investigations were performed in the 1980s and 1990s to refine site characterization and develop a preliminary design that included measures to improve sliding and overturning stability. Investigations included field testing to directly assess uplift and drain efficiency. Design assumptions for drain efficiency were then developed by empirically reducing the measured values from the field study based on the location and number of anchors planned for each monolith to account for possible increases in uplift pressures that could result from changes in rock mass permeability caused by anchor borehole grouting. Stability evaluations using the updated loading and parameters determined that the dam would become unstable at pools less than the top of dam.

Modifications, currently underway, include installation of over 550-fthigh capacity rock anchors. Installation of most anchors was completed in 2017 and uplift pressures have been re evaluated. Results show a mix of conditions ranging from no impacts to significant increases in uplift pressures for some monoliths that can be closely correlated to anchor borehole grouting. This presentation will illustrate the relationship between uplift, rock foundation conditions, and grouting at this site and discuss the complexity of extrapolating drain efficiency design assumptions that must be valid for the future, post construction condition.

Mapping Increases in Hyporheic Exchange from ChannelSpanning Logjams Doughty, Megan, Colorado School of Mines, Army Corps of Engineers, megan.jean.colorado@gmail.com; Audrey Sawyer, sawyer.143@osu.edu; Ellen Wohl, Ellen.Wohl@colostate.edu; Kamini Singha, ksingha@mines.edu (Poster) Logjams increase hydraulic resistance and create hydraulic head gradients along the streambed that drive groundwater-surface water exchange. Here, we quantify changes in hyporheic exchange flow (HEF) due to a channel-spanning logjam using field measurements and numerical modeling in MODFLOW and MT3DMS. Electrical resistivity (ER) imaging was used to monitor the transport of solutes into the hyporheic zone during a series of in-stream tracer tests supplemented by in-

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AEG 2020 VIRTUAL ANNUAL MEETING stream monitoring. We conducted experiments in two reaches in Little Beaver Creek, Colorado: one with a single, channel-spanning logjam and the second at a control reach with no logjams. Our results show that 1) higher HEF occurred at the reach with a logjam, 2) logjams create complex HEF pathways that can cause bimodal solute breakthrough behavior downstream, and 3) higher discharge rates associated with spring snowmelt increase the extent and magnitude of HEF. The numerical modeling supports all three field findings, and also suggest that lower flows increase solute retention in streams, although this last conclusion is not supported by field results. This study represents the first use of ER to explore HEF around a naturally occurring logjam over different stream discharges and has implications for understanding how logjams influence the transport of solutes, the health of stream ecosystems, and stream restoration and conservation efforts.

Analysis of High Priority Unstable Rock Slopes in Great Smoky Mountains National Park, Tennessee and North Carolina Farmer, Samantha, East Tennessee State University, farmersl@etsu.edu; Thomas O’Shea, osheat@etsu.edu; Arpita Nandi, nandi@etsu.edu (TS #7) Great Smoky Mountains National Park (GRSM) in Tennessee and North Carolina is the most visited national park in the United States, receiving 12.5 million visitors in 2019. Annually, GRSM experiences unanticipated rockfall failure events that obstruct flow of traffic and pose significant risk to visitor safety. This project focuses on 1) rockfall susceptibility analysis of GRSM using MaxEnt, and 2) a rockfall risk map of GRSM roadways using ordinary kriging. Unstable slope data were collected using the Unstable Slope Management Program for Federal Land Management Agencies (USMP for FLMA) Slope Rating protocols. A total of 253 slopes were studied along 186-mile-long roadway, of which 223 were identified as planar or wedge rockfall types. Slopes were rated as poor, fair, or good based on a preliminary rating, total hazard score, and total risk score. A rockfall susceptibility model was created using seven WorldClim bioclimatic variables, including mean temperature coldest month, wettest quarter, and coldest quarter: annual precipitation: and precipitation of wettest month, wettest quarter, and coldest quarter. The model produced an AUC of 0.988 and commission of 0.642. The results from the susceptibility model validates field observations with the most susceptible roadways as the Spur, Newfound Gap Road, and Little River Gorge Road. Using ordinary kriging, a rockfall risk map identified the Spur and Newfound Gap and Little River Gorge Roads as the highest risk roadways. The kriged surface produced a Root-Mean-Square (RMS) value of 136, Mean Standardized value -0.059, and an RMS Standardized value 1.129. Co-kriging using geology, precipitation, fault proximity, slope, and elevation indicated an improvement in model diagnostics. Outcomes from this project hope to improve communication amongst GRSM officials, researchers, stakeholders, and third parties through identifying areas most susceptible to rockfalls, visualization of high-risk areas, and improve safety along GRSM roadways.

Influence of Bedrock Substrate on Mobility of Large Rock Avalanches Formed in Dry Climates: Blue Diamond Landslide Case Study Ferry, Nicholas, University of Cincinnati, nicholasferry90@gmail.com; Daniel Sturmer, sturmedm@ucmail.uc.edu (TS #7) Large rock avalanches are high velocity mass wasting events that pose potential threats to population centers and infrastructure far from their source. The mechanisms that govern their mobility have been studied for over a century, yielding many explanations for their unusually long runout distances. Whereas most of these hypotheses address intrinsic 36

mechanisms, few have addressed the role of runout path substrate material. This study investigates the influence of a rigid bedrock substrate on the mobility of the Blue Diamond landslide deposit, which is located 20 km west of Las Vegas, Nevada. Sedimentary fabrics and internal morphologies were identified and mapped following standard facies models for large-rock avalanche deposits formed in dry climates.

The presence of a basal mixed zone and fault gouge rules out a frictionless emplacement, instead representing prolonged interactions at the rock avalanche—substrate interface, which indicates significant basal shear resistance was endured during motion. However, estimates of the apparent friction coefficient indicate low to moderate resistance.

Distribution of sedimentary fabrics suggests reduced frictional resistance was likely generated by additional mechanisms acting on the translating rock mass. Variation in clast lithology proportions throughout the deposit helps explain the intrinsic mechanisms occurring in the slide mass. Correlations between matrix and carbonate clast count frequencies show that areas with more matrix experience substantial amounts of fragmentation and comminution. Basal shear stresses were transmitted upward through the rock mass during emplacement resulting in a vertical transition upward from matrix-rich to matrix-poor breccia facies. Proportional breakage and enhanced mobility may best be explained by the process of dynamic fragmentation.

Pumice Mine Reclamation, Oregon State University – Cascades Campus, Bend, Oregon Freitag, George, GRI, gfreitag@gri.com; Mike Marshall, mmarshall@gri.com; Greg Martin, gmartin@gri.com; Nora Utevsky, norautevsky@gmail.com (TS #7) In 2012, Oregon State University obtained 76 acres of land for an expansion of the Cascades campus in the west portion of Bend. Beginning around 1950, the land was logged and used for open-pit mining of Bend Pumice (BP; 180ka). Mine depths were ultimately up to 100 ft below adjacent grades resulting in spectacular exposures of rock units above and below the BP. Some of the pits were reclaimed as engineered landfills and others with non-engineered fill. In 2008, a strand of the Quaternary Metolius fault (MF) was mapped by the USGS across the site. Engineering geology mapping of pit wall units, primary volcanic features, paleoliquefaction features, and faults was completed during grading to guide campus planning. No areas of undisturbed soils that could bracket MF last on-site displacement age <11ka were found; therefore, for campus planning the MF is considered an ageindeterminate zone and managed as potentially Holocene active. Units exposed include fill; Shevlin Park Tuff (SPT; 170ka), Tumalo Tuff/BP, alluvial unit 2 (AU2); Desert Springs Tuff (DST; 600ka); and AU1. Mapping shows BP and AU2 were deposited on an erosional surface of DST. Mapping and trenching disclosed three strands of the MF, with apparent vertical offsets up to 33 ft. Marker bed contacts including the SPT/Tumalo Tuff, the Tumalo Tuff/BP, and BP/AU2, large primary cooling joints in the DST, and stratigraphic layers in DST were used to guide campus improvement areas outside a 50 ft setback from the MF.

Back-Analysis of Unlined Rock Spillway Erosion Rates to Support Risk-Informed Design George, Michael F., BGC Engineering Inc., mgeorge@bgcengineering.com; Coralie Wilhite, Coralie.P.Wilhite@usace.army.mil (TS #8) The Richard L. Schafer Dam (formerly Success Dam) and reservoir are operated and maintained by the US Army Corps of Engineers. The dam is located about six miles upstream of the City of Porterville, California on the Tule River and provides flood damage risk reduction, agricultural water supply, and recreation. The dam has an unlined rock spillway excavated into the right abutment that discharges to a natural

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING drainage channel. During its history, the spillway has operated one time, which occurred in 1966 with a peak discharge of 8,300 cfs.

Although erosion of the unlined spillway channel did not occur, erosion was observed in the natural drainage immediately downstream of the excavated spillway. Proposed modifications to the spillway, consisting of a crest raise and widening, were supported by a baseline risk assessment to provide additional flood risk reduction and irrigation water supply. Proposed structural features include a 10-ft-high reinforced concrete ogee weir, reinforced concrete sidewalls anchored into rock, and a concrete apron with downstream concrete cutoff wall.

To support the risk-informed design, an erodibility study was performed to assess scour potential of the proposed spillway configuration. Of concern was the potential for scour originating in the downstream drainage channel to migrate upstream and cause an uncontrolled release from the reservoir by first undercutting and damaging the proposed apron and walls, then breaching the ogee structure. Information on erosion rates in rock, however, is limited in literature, which can make time-rate-of-scour analysis challenging. For this study, however, documented erosion from the 1966 event could be used to perform back-analysis of rock erosion rates, which were ultimately utilized for predictive analysis for future design spill events.

This presentation focuses on details of the back-analysis performed to estimate rock erosion rates that were used to support risk-informed design of the proposed spillway modifications.

History of Internal Erosion at East Branch Dam, Pennsylvania, and Cutoff Wall Remediation Project Greene, Brian, Gannett Fleming, Inc., bgreene@gfnet.com; Greg Braun, gregory.d.braun@usace.army.mil (TS #5) East Branch Dam is a Pittsburgh District, US Army Corps of Engineers project completed in 1952. The dam is a zoned embankment 184 feet high and 1,725 feet long. The primary purpose of the dam is flood control, however, it also provides water supply and recreation. In May 1957, muddy water was observed flowing from a rock drain at the downstream toe of the dam by project personnel. Drilling exposed a void located just above the dam’s shallow cutoff trench, which led to an immediate pool lowering and emergency grouting. Repairs consisted of filling the void with grout and consolidation grouting of the surrounding area of the embankment. The fundamental conditions that caused the original problem were not corrected by the 1957 emergency repairs. In 2006, the dam was evaluated under the USACE Screening Portfolio Risk Assessment (SPRA) program. Interim risk reduction measures were implemented in 2008, with the primary measure involving lowering the upstream pool. In 2010, a Dam Safety Modification Study was completed and recommended a seepage barrier wall as the remediation alternative to reduce the dam safety risk to tolerable levels.

Consequently, a comprehensive remediation of the dam was designed to consist of a full-depth, full-length cutoff wall through the embankment into foundation bedrock. The cutoff wall installed at East Branch Dam was constructed using two Bauer hydromill rigs. The wall consisted of 149 concrete panels with final depths ranging from 90 ft to 245 ft. The cutoff wall was comprised of single bite and triple bite primary panels 32-in-wide, and single bite closure panels 42-in-wide with a 6-in minimum overlap. Some challenges during construction included slurry loss in pervious rock fractures and concrete panel settlement.

Cutoff wall construction was completed in 2020 and immediately favorable instrumentation responses were observed.

September 2020

Flood History and Landslide Dam Hazards of the Montecito Watersheds, Santa Barbara County, California Gurrola, Larry D., The Partnership for Resilient Communities, lg@larrygurrola.com; J. David Rogers, rogersda@mst.edu (TS #6) On January 9, 2018, a series of destructive debris flows devastated the community of Montecito, adjacent to Santa Barbara, California.

Funded by the Partnership for Resilient Communities, this study’s goal is to reduce the hazards of debris flows by identifying suitable sites for debris basins along the principal watercourses. Methodologies include fire, flood, and landslide dam research; aerial photographs and field mapping; and lidar, geomorphologic, and hydrologic analyses.

Numerous bedrock landslides mantle steep slopes developed in Tertiary sedimentary rocks that pinch channels and form obvious knickpoints.

Most of these landslides blocked channel flows with slide debris forming temporary lakes, with blockages that are typically overtopped within 12 to 24 hours. Outbreak floods often increase peak discharge far in excess of what might be generated by natural concentration of overland flows. Most of the breached dams appear to be result of deep-seated landslides in confined bedrock canyons, with basal slip surfaces, often revealed by active toe undercutting and channel incision.

Historic records establish that at least thirteen debris flow and debris laden flood events have occurred in the Montecito watersheds including 1825, 1861–62, 1872, 1879, 1889, 1914, 1926, 1964, 1969, 1971, 1995, 2018, and 2019. These events vary in magnitude from small, affecting one or two watersheds, to large (January 9, 2018, event). Comparison of 1914 flow paths in the Montecito and San Ysidro Creek watersheds with 1926, 1964, 1969, and 2018 flow paths and inundation areas reveal similar flow paths and avulsion sites. One of the largest landslides was reported in 1909, which was visible from downtown Santa Barbara, 7.25 km away. The formation and collapse of landslide dams in the 1914 event was described where multiple landslide dams formed and quickly collapsed in a downstream succession.

Another landslide dam outbreak event was reported in 1926 in post-fire conditions of the San Ysidro watershed.

Residential Property Annual Slope Movement Monitoring in Erwin, Tennessee Harris, Sarah, East Tennessee State University, Department of Geosciences, harrissl1@etsu.edu; Michael Whitelaw, whitelaw@etsu.edu; Arpita Nandi, nandi@etsu.edu (Poster) Mass movements are a constant threat in the mountains of East Tennessee. This study reports on a monitoring project conducted on a residential property located on an active hillslope with three documented mudslide events since 2012, the latest on April 13, 2020. The property is located at the toe of Looking Glass Mountain, Erwin, Tennessee, and has multiple risk factors that suggests further movement is likely. The house is placed on a thin, 3-m alluvial conglomerate which overlies the Buffalo Mountain thrust and well-bedded phyllitic dolomites that both dip subparallel to the 25-ft hillslope. The house foundation and driveway sit 20 miles above an access road that parallels Little Indian Creek. The slope immediately below the house has been over-steepened to 50 feet by construction of the access road and further destabilized by poorly directed drainage from the house roof and removal of vegetation to enable a view of the creek. In order to monitor slope motion a grid of 43 steel pins was placed along the driveway, below the house, and at the access road entrance. All sites were surveyed with a laser range finder every two weeks from June 2019 to April 2020. Rainfall data was collected to allow comparison between rainfall events and slope movement. An Unmanned Aerial Vehicle (UAV) was used

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AEG 2020 VIRTUAL ANNUAL MEETING to provide photogrammetry of the site to better characterize slope topography and drainage and to document the April 2020 event.

Pin survey data indicates that there was an average of 0.153 m of downslope motion between June 2019 and March 2020 indicating soil creep, which mobilized into a mudslide on April 13, 2020, at the property’s access road entrance. The slope movement at the site is significantly positively correlated (r = 0.69 at p < 0.05) with regional rainfall accumulation.

Hydrogeologic Characterization of the C-23/24 North Reservoir Dam Site, Indian River Lagoon–South Watershed, Florida Hayes, Kevin, US Army Corps of Engineers, kevinhayespg@gmail.com (TS #8) Investigations conducted in 2019–2020 at the C-23/24 North Reservoir site in St. Lucie County, Florida were designed to provide subsurface geotechnical and hydrogeologic data to meet project design needs. Twenty-two, Surficial Aquifer System (SAS) monitoring wells were installed around the approximately 8.5 mile perimeter of the proposed earthen embankment. The wells were drilled to depths of 20, 35, 55, and 100 feet below ground surface (BGS) to evaluate the approximately 110-ft-thick SAS. Slug testing (ASTM D4044) conducted on three sets of four nested well clusters yielded 61 tests in total. Twenty-four borings were drilled within the embankment footprint to conduct recharge tests (USBR 7310) within the shallow foundation materials, including a clayey sand (SC) interval, a weathered limestone layer, and a sand-shell (SP) interval. The recharge tests were conducted at depths of 23.5 feet BGS or less (upper portion of the shallow SAS). Shelby tube samples of shallow foundation soils and deeper zones of the SAS exhibiting higher percentages of fine-grained materials were collected for lab permeability testing (ASTM D5084). The highest horizontal hydraulic conductivity (Kh) values were exhibited by the sand-shell (SP) interval of the shallow SAS with average slug testing and recharge testing-derived values of 102.9 and 52.5 feet/day, respectively. The middle and deep SAS zones exhibited significantly lower average Kh values of 1.4 and 3.1 feet/day, respectively, based on slug test data. The shallow clayey sand (SC) and limestone intervals overlying the sand-shell (SP) zone exhibited average recharge testing-derived Kh values of 0.30 and 0.58 feet/day, respectively. Average vertical hydraulic conductivity (Kv) values for the shallow clayey sand (SC) and the middle SAS zones were 0.015 and 0.11 feet/day, respectively, based on lab permeability testing. Aquifer pumping tests are scheduled for summer 2020.

King City Siphon – Challenging Ground Conditions Drive Alignment Selection for a Vertical Curve Microtunnel Headland, Paul, Aldea Services, pheadland@aldeaservices.com; Ashley Heckman, aheckman@aldeaservices.com (TS #1) The King City Siphon, which crosses the Tualatin River, forms part of the Tualatin Interceptor and Siphon Improvements (TISI) Project located in Portland, Oregon, under a design-build contract mechanism. The siphon comprises a 470-ft-long, 84-in-diameter tunnel with a 650-ftradius vertical “U” curve. A reinforced concrete casing pipe, designed to incorporate the JackControl hydraulic joint system, was installed using a new Herrenknecht AVN 1800 machine (with double-steering articulation) inside which carrier pipes were inserted comprising a 26-in HDPE DR32.5 line (high flow barrel), a 16-inch HDPE DR32.5 line (redundant flow barrel) and a 14-in HDPE DR21 line (low flow Barrel). To achieve the vertical curve, the pipe and pipe joint geometry, curve radii, required jacking force capacity, and MTBM articulation joints were specifically designed to meet the project constraints. The ground condi38

tions comprise Alluvium (medium-plasticity lean clay and non-plastic silt), Missoula Flood Deposits (stiff to very stiff clay and soft to medium dense silt), and the Hillsboro Formation comprising very stiff, hard, medium to high-plasticity lean and fat clay. Groundwater at the site is within 5 feet of ground surface. The presence of “potentially liquefiable zones” were identified within the Missoula Flood Deposits. The paper describes the evaluation of vertical alignment alternatives based upon challenging ground conditions and ground behavior and the development of the “lowest risk, best value solution.”

GPR Investigation of Mine Subsidence Hazards in Charlotte, North Carolina Heavener, Emma, UNC Charlotte, estadick@uncc.edu; Andy R. Bobyarchick, arbobyar@uncc.edu (Poster) North Carolina gold mines were a leading part of the minerals infrastructure in the 19th and early 20th centuries. Although production from registered mines was monitored by regulation, detailed maps of surface operations and underground access networks exist for only a few of the larger mines. When the mines ceased operations, land was sold for agriculture and ultimately for commercial and housing development. Shafts in some mines may have been backfilled, but it appears that stopes and some drifts may have been abandoned as is. Roof supports in drifts were typically large timbers and lumber.

Some drifts were excavated to within a couple of feet of the ground surface. Since abandonment, settlement, ground water flow, and timber rot sometimes lead to collapse of near-surface voids and formation of sinkholes. Subsidence appears as rectangular depressions or conical collapse funnels. We investigated a potential mine collapse under the foundation of an urban Charlotte home to explain the relationships between the shallow subsurface geology and the origins of and hazards associated with the sinkhole. The home is near the approximate location of the historic Chinquepin Mine. Abandoned structures from the mine burned in 1895. To search for uncollapsed voids, we conducted a GPR survey on the bare earth basement floor with 400 MHz and 100 MHz antennas and also a 400 MHz reference survey in an adjacent grassy field. 3D models show several void-like features in the subsurface, one connecting to an open sinkhole. Data from the neighboring grassy field also reveal characteristic anomalies of partially filled voids. The home and neighboring area are built over remnants of mine excavations, and because ground subsidence has already occurred over part of these excavations, we suggest that future sinks of similar magnitude may occur.

Development of a Geotechnical Model for Open Pit Slope Design in Cenozoic Sediments in the Pilbara Region of Australia Hemraj, Dylan, Pells Sullivan Meynink, dylan.hemraj@psm.com.au; Mark Eggers, mark.eggers@psm.com.au (TS #7) This paper presents a case study, which uses a novel approach to development of the geotechnical model for open pit slope design. The method uses the resource geochemistry and downhole geophysics database in addition to the traditional geotechnical drilling methods to help build the geotechnical model. The case study is from an iron ore mine located in the Pilbara region in North West Australia. The deposit area is approximately 18 km by 13 km located on the south side of the Chichester Range and north of the Fortescue Valley. The deposit is covered by a 100m-thick Cenozoic aged sequence of sediments comprising mudstones, clays and conglomerates. High pit walls are to be developed in the cover sequence making it important to the geotechnical model. The challenges for developing the geotechnical model include pits situated over a large area, limited historic geotechnical/ diamond drilling, limited investigation budgets, high degree of uncer-

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING tainty in the existing Cenozoic geological model, and requirement to elevate the current understanding from pre-feasibility to execution level.

The approach comprises comparing selected reverse circulation resource drill results against adjacent diamond core drilling with detailed geotechnical logging. The aim is to assess key geochemical and geophysical signatures for the major geotechnical units. These signatures are then applied to selected sections through the resources drilling database from which the geotechnical model is interpreted.

Modelling includes developing an engineering geological model encompassing the paleo-valley formation and the resulting deposition of the Cenozoic cover sequence to help interpret the geometry of key units between data points. The resulting model helps identify areas of high geotechnical risk and guides analysis of critical failure mechanisms, which has resulted in steepening of inter-ramp angles in some areas and development of pit slope risk management strategies. The resulting model helps identify areas of high geotechnical risk and guides analysis of critical failure mechanisms, which has resulted in steepening of inter-ramp angles in some areas and development of pit slope risk management strategies.

Phased Approach for Evaluating Piezometers to Inform a Risk Assessment, Blakely Mountain Dam, Ouachita River, Arkansas Hess-Brittelle, Suzanne R., US Army Corps of Engineers, suzanne.r.hess-brittelle@usace.army.mil; Amy F. LeFebvre, amy.f.lefebvre@usace.army.mil (TS #5) Blakely Mountain Dam is located on the Ouachita River, approximately 10 miles northwest of Hot Springs, Arkansas. Completed in 1953, the project includes a 240-ft-high earth-fill dam, open-cut spillway, controlled outlet works, and powerhouse with related structures. Multiple open pipe piezometers were installed in the upstream/downstream embankment shells, impervious core, core/foundation contact, and downstream drainage blanket. As part of a subsequent piezometer flushing effort, one piezometer began exhibiting behavior that suggested the embankment or foundation may have been damaged. The project was studied as part of USACE’s ongoing risk informed management of dams in its portfolio, in part due to concerns related to embankment and/or foundation damage and continued anomalous behavior of previously flushed piezometers. As part of this assessment, a non-invasive field investigation was conducted to determine functionality of piezometers before deciding if a more costly invasive drilling program was warranted. Results of the non-invasive investigation will be presented as well as impacts to the risk assessment.

Analysis of Geohydrological Risks Based on SR & GIS from the Southeast Portion of the City of La Paz, Baja California Sur, Mexico Hirales-Rochin, Joel, Area of Earth Sciences, Department of Civil Engineering, Technological Institute of La Paz, joelhirales@itlp.edu.mx (Poster) Geological and hydrometeorological risks are currently responsible for the high levels of affectation and destruction in urban areas, in the twentieth century alone it is estimated that more than one million people worldwide have died as a result of earthquakes. In Mexico annually, more than 50% of the disasters that occur in the country are triggered by phenomena of hydrometeorological origin, hurricanes and other types of torrential rains stand out, being Baja California Sur the entity with the highest incidence of cyclones on average in the Ocean Northeast Pacific Therefore, the capital city La Paz is characterized by intermittent surface hydrology and lack of rivers. However, the plain in which these runoffs are distributed until they flow into the Bay of La Paz, originate important areas of flooding in the peripheral September 2020

area of the city. The methodology to achieve the objectives was based on the compilation of information from the study area, data collection and observation of geohydrological conditions. All this information was complemented with RS and GIS technology compatible with satellite data prepared in ArcGIS software. Finally, several thematic maps and a final map of vulnerability to geohydrological risk were generated. The results contribute with new geotechnical knowledge to be used in the most precise zoning of geological and hydrogeological risks and which together are useful for the planning and sustainable urban development of La Paz City.

Dog Valley Fault as a Potential Threat to Stampede, Prosser Creek, and Boca Dams Hobart, Catherine, Baylor University, Kate_hobart1@baylor.edu; Vince Cronin, Vince_cronin@baylor.edu; Joseph White, Joseph_white@baylor.edu; John Dunbar, John_dunbar@baylor.edu (Poster) This is a progress report on efforts to locate the ground-surface trace of the Dog Valley Fault (DVF) near Truckee, California. The DVF generated a M6.0 earthquake in 1966, prior to completion of Stampede Dam by the US Bureau of Reclamation in 1970. USBR geologists found a 3–9-m-thick clay-gouge zone in the left dam abutment during pre-construction exploration (Hawkins et al., 1986), which seems likely to be along the DFV. The DVF trace probably also crosses Prosser Creek Reservoir. Today, a M6+ earthquake that causes surface rupture along the DVF might induce failure of Stampede Dam, compromising Boca Dam downstream. The resulting flow of water and debris would endanger people and infrastructure along the Truckee River to Reno, Nevada. A USBR report in 2012 stated, “…approximately 148,400 people living downstream from [Stampede] dam would be impacted in the event of dam failure [including] a large portion of the city of Reno,” (USBR, 2012, p. B14-B15). To date, we have focused on 1) seismo-lineament analysis and statistical best-fit-plane evaluation of relocated earthquakes and 2) structural-geomorphic analysis of hillshade maps based on 1-m DEMs created from lidar data. This analysis includes lineament mapping with GIS-based techniques such as convolution filtering, drainage network analysis, and stream deflection mapping, augmented by additional soil survey and near infra-red vegetation data to identify possible faults. We will also use GPS-site velocity data to measure present-day crustal strain in the area of the DVF. When it is safe to resume field studies after the COVID health crisis, we will conduct electromagnetic induction (EM) and DC-resistivity surveys across suspected DVF traces, which should improve prospects for successful paleoseismic trench studies in the future.

Debris Flow Inventory and Hazard Assessment in Sitka, Alaska Hubbard, Trent, State of Alaska, Division of Geological & Geophysical Surveys, trent.hubbard@alaska.gov; Ronald Daanen, Ronald.Daanen@alaska.gov (TS #6) The threat of landslides poses significant safety and financial risk to people and infrastructure in many communities throughout Alaska, including the City and Borough of Sitka. To better inform the southeast Alaska community of potential landslide hazards and increase the City’s hazard resiliency, the Alaska Division of Geological & Geophysical Surveys created maps of historical landslides, shallow landslide susceptibility, and simulated debris flow runout to assess landslide hazards in and around the community. The historical landslide inventory map integrates existing mapped landslides with additional landslides identified using newly acquired high-resolution lidar. A shallow-landslide source susceptibility map was created following protocols similar to those developed by the Oregon Department of Geology and Mineral Industries, incorporating published and

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AEG 2020 VIRTUAL ANNUAL MEETING generic geotechnical data and lidar slope data to calculate Factor of Safety (FOS), which was used to categorize landslide susceptibility. We used physical parameters calculated based on the 2014 Starrigavan debris flow and the 2015 South Kramer and Silver Bay debris flows in the Sitka area to calibrate the computer model LaharZ and generate simulated debris flow runout extent maps. We used catchment size and slope derived from lidar to scale each catchment to the volume of debris. Data from the three analyses were combined to produce an integrated debris flow map intended to depict overall potential hazard.

The results provide important information about landslide hazards that can help guide planning and future investigations.

ments. The new LEED requirements for Radon will also be covered.

There will be a review of the occurrence of Radon in groundwater and the health effects of ingesting Radon contaminated water will be discussed. The requirement for mandatory testing for Radon in water will be discussed and a new down the well mitigation method will be presented. Case studies will be included as part of the presentation.

Are Low-Cost Monitors Good Enough to Help People Understand Poor Air Quality in Their Neighborhood?

Subtle differences between the hydrogeologic and geomechanical behaviors of carbonate reef deposits and the surrounding carbonate strata can adversely impact tunnel excavation and construction if not identified, characterized, and anticipated prior to exposure during excavation. Insitu packer test results do not appear to accurately distinguish the true, order-of-magnitude differences in hydraulic conductivity between reef and non-reef facies in the Silurian Dolomites.

Engineering geologic knowledge and understanding of the terms primary and secondary hydraulic conductivity, the differences between them, the differences between porosity and effective porosity, and the implications of these aspects of carbonate reef are crucial components of proper characterization. Specific laboratory tests have been found to accurately allow engineering geologist to distinguish these problematic lithofacies along tunnel alignments and to segregate strength and characteristics data within both the geotechnical data and baseline reports for tunnel projects. Methods to address the adverse ground behaviors of reef will also be discussed.

Ilie, Ana Maria Carmen, Colorado School of Mines, ailie@mines.edu; Holger M. Eisl, heisl@qc.cuny.edu (Poster) There is a growing field of “citizen scientists,” non-scientists engaged in specific issues who collect or analyze data to contribute to scientific research or advocate for environmental or public health improvements.

Specific aims of this study included the increase of citizen engagement in accessing, collecting, and communicating air quality data, to provide tools to better inform communities on air quality issues; and, increased data collection in communities that can offer additional spatial and temporal data on pollution levels beyond existing New York City Community Air Survey (NYCCAS) program and regulatory methods in the New York City. It explored the feasibility of using stationary low-cost monitoring networks for spatial and temporal estimation of ambient fine particulate concentrations (PM2.5) in an environmental justice community in New York City—El Puente, in Brooklyn a borough which is characterized by a high rate of asthma and cardio-respiratory issues due to the presence of high levels of particulate matter in the atmosphere. The study area is located close to Brooklyn-Queens Expressway and Williamsburg Bridge.

The data collection started in March 2019 and lasted until November 2019. Based on the R-squared value a strong agreement was observed between FEM and AirBeam2 low-cost monitors. As a part of citizen science, the act of monitoring pollution by citizens themselves facilitated learning and increasing their awareness of environmental issues by changing the public attitude towards science and the environment.

Through this work, citizens had the opportunity to have access to informational tools that helped them understand the distribution of health outcomes as a result of air pollution, identify areas with highest PM2.5 concentration and avoid harmful exposures to their bodies. Detailed data analysis with fine-scale monitoring helped create a rich datasets useful for addressing public health uncertainties.

New Technologies for Testing and Mitigating Radon in Air and Residential Well Water plus a Radon 101 Review of Health Effects Innes, David, Director of Sales, Radon Environmental Management Corp, Vice President of the Canadian Association of Radon Scientists and Technicians (CARST), david.innes@radoncorp.com Radon is responsible for approximately 23,000 radon induced Lung Cancer deaths per year in the United States! This 45-minute power point webinar will cover the basics of Radon including the health effects associated with exposure to Radon in air and water. New technology methods for testing for Radon in air will be examined along with the benefits and drawbacks of each method. We will look at Radon mitigation in new construction and existing buildings. A comparison of sub slab depressurization and the use of Air handling as a mitigation tool will be discussed. The various Radon action levels will be compared as well as a look at the real estate transaction require40

Identification and Adverse Impacts of Carbonate Reef Structures for Tunnel Projects Isaacson, J. Ike, Brierley Associates, iisaacson@brierleyassociates.com (TS #1)

Interrelationship of Faulting and Landsliding in the San Bernardino and San Jacinto-Santa Rosa Mountains Jordan, Frank, County of San Bernardino, Land Use Services Department, geo.jordan@gmail.com; Kerry Cato, kerry.cato@csusb.edu (TS #6) Current geologic mapping does not appropriately recognize the intricate relationship between fault and landslide formation, other than as a generalization. Published geologic mapping frequently fails to recognize significant fault features expressed geomorphically across the surface, rendering, at best, an incomplete picture of the tectonic history of an area. Existing published maps identify many of the larger, tectonically active faults; however, the efforts fall short of recognizing the geomorphic expressions characteristic of gravitationally derived mass wasting events (landslides), and the resultant geomorphic expressions of erosional processes that develop upon the affected rock masses.

Previous mapping efforts relied on field reconnaissance, review of stereoscopic aerial photographs, and outdated tectonic and gravitational models. Our efforts to re-evaluate the fault and landslide mapping in the San Jacinto and Santa Rosa Mountains in Southern California show numerous examples of misclassifications of both processes.

Here, compressional tectonism, through reverse and thrust faulting, have lifted the rock masses above the surrounding plains and valleys, while translational tectonism, in the form of strike-slip and oblique-slip faulting, have shifted the rock masses laterally, creating deep gashes that act as weakened boundaries between rock masses. The process of mass wasting in igneous and metamorphic materials is inextricably linked to saturation of the rock by groundwater. This component of the relationship suggests that failure of large rock masses initially originated during Pleistocene time, when precipitation was considered to be much greater than during the Holocene. Through the use of 3D mosaicked aerial imagery in both plan and vertically exaggerated perspectives, new in-sight can be gained of geologic processes associated

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING with both tectonic and gravitational forces. The re-evaluation of both processes and hazards lead to a better geologic understanding of the potential geologic hazards facing site evaluations of developments both large and small.

Asbestos Monitoring in Construction Site Air – Unexpected Challenges to Construction Site Monitoring Kalika, Sarah, DiabloGeo Environmental Consulting, skalika@diablogeo.com (TS #3) In the San Francisco Bay Area, area asbestos air monitoring is required for construction projects greater than 1 acre that contain any amount of asbestos. While this is intended to be an indicator to encourage construction personnel to maintain adequate dust control during earthwork, unexpected surprises can appear in air sample data. This presentation will summarize a project in the San Francisco Bay Area and what was discovered within air samples that were collected during import of “non-NOA” containing gravel from a nearby quarry, while gunite was sprayed on an excavation sidewall, and when off-site construction, fires, and vehicle traffic resulted in impacts to construction site air.

When Can Four-to-Twelve Tests Be Sufficient for Engineering Design Parameters? A Tale of Two Papers Keaton, Jeffrey, Wood, jeff.keaton@woodplc.com; Abdul Shakoor, ashakoor@kent.edu (Poster) “It depends…” is the only logical answer. The title of a 2019 Environmental & Engineering Geoscience paper posed the question, “Are three to ten tests enough to characterize a rock property?” and cited a 2014 paper entitled, Selection of Geotechnical Parameters Using the Statistics of Small Samples, with an example using four and 12 tests.

Among the many references cited in the 2019 paper was one written by three authors in 2005 with the title, Determining the Minimum Number of Specimens for Laboratory Testing of Rock Properties.

Among the few references cited in the 2014 paper was a second 2005 paper by the same three authors entitled, A Statistical Approach for Determining Practical Rock Strength and Deformability Values from Laboratory Tests. This contrasts science, seeking to explain and predict, with engineering, seeking to design with multiple constraints. The 2019 paper concludes that ten or fewer measurements are too few to capture the inherent variability of rock properties.

The 2014 paper begins with “Selection of parameters for geotechnical calculations frequently is based on results of relatively few laboratory tests that are used to guide judgment of experienced engineers.” It concludes that rigorous statistical procedures provide a method for data analysis in which target values of confidence interval, precision index, and stability probability are treated explicitly, which provides a way of analyzing test results that allows uncertainty and variability to be quantified for use in probabilistic stability analyses and the value of additional test results to be demonstrated. The two 2005 papers were written by professors from a university department that includes mining engineering; mining companies use rigorous statistical analyses of mineral assay results for economic decisions. It should be no surprise that feasibility-level stability analyses of large open-pit mines use practical strength values from rigorous statistics on a handful of tests.

September 2020

Climatic Controls on the Kinematics of the Hooskanaden Landslide, Curry County, Oregon Kingen, Kara, Portland State University, kkingen@pdx.edu; Adam Booth, boothad@pdx.edu; Ben Leshchinsky, Ben.Leshchinsky@oregonstate.edu (Poster) Slow-moving earthflows represent major sources of sediment transport and erosion and are problematic for the management of critical infrastructure. The Hooskanaden Landslide—a slow-moving earthflow on the southwest coast of Oregon—crosses US Highway 101 and has been a site of particular interest to the Oregon Department of Transportation due to the weak lithology, erosive environment, and recurrent surge behavior (every ~15 years). Past surges, including the most recent (2019), have occurred during the winter, suggesting that velocity changes are predominantly controlled by climatic inputs.

To examine the response of the Hooskanaden Landslide to seasonal and other periodic climate cycles (such as El Niño–Southern Oscillation), manual feature tracking on satellite images from PlanetLabs was used to create a surface velocity time series from 2009 to late 2019. In comparing our velocity time series to precipitation records from the area, it is clear that periods of seasonal acceleration correspond with above average precipitation. However, surges did not correspond to years with the highest seasonal precipitation, although they did correlate with El Niño years. Additionally, extensive surface mapping and carbon dating were performed to understand the morphology and origins of this landslide. Three tree rounds were cut from logs previously buried at the toe of the landslide and subsequently exposed by erosion for radiocarbon analysis using wiggle matching.

Possible ages of samples were constrained using stratigraphic, dendrochronological, and varve models within OxCal. Based on agreement between multiple calibration models over two sets of samples, we estimate that this slide has been active since ~1750 AD—several decades after the last Cascadia Subduction Zone earthquake. Given its age, measurable annual displacements, cyclic surge behavior, and continuous erosion at the toe, it is likely that this earthflow will continue to be active for the foreseeable future.

Historic Analysis and Future Expansion of the EisenhowerJohnson Memorial Tunnels, Part 1: Geologic Modeling Krajnovich, Ashton, Colorado School of Mines, akrajnov@mines.edu; Gauen Alexander, galexander@mines.edu; Wendy Zhou, wzhou@mines.edu; Marte Gutierrez, mgutierr@mines.edu (TS #1) The Eisenhower-Johnson Memorial Tunnel (EJMT) is a pair of two-lane vehicular tunnels carrying Interstate 70 under the continental divide in Colorado. The original construction encountered highly variable geologic conditions from massive intact granite to squeezing fault gouge.

Ongoing research is informing the future expansion of the EJMT and focuses on two parts: geologic modeling and geotechnical analysis.

The primary focus of geologic modeling is on characterizing major fault zones which intersect the tunnel, believed to be associated with the nearby, regional Loveland Berthoud Pass fault zone. A probabilistic geomodelling approach is developed to characterize the uncertainty about the location and geometry of fault zones in the subsurface based on various levels of information. The uncertain geologic model is then validated and updated according to new observations, providing an opportunity to rectify observations of fault zones made at the surface (i.e., through geologic maps and photogrammetric outcrop surveys) with similar observations at tunnel grade recorded in a pilot bore geologic map. The validated 3D geologic model takes into consideration all available information and observations to describe the most likely geometry of the network of fault zones intersecting the

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AEG 2020 VIRTUAL ANNUAL MEETING EJMT. This structural model is subsequently used as a platform for analyzing rockmass quality in the vicinity of the existing tunnels.

Preliminary Investigation of Slope Movements in the North Cove Area, North Carolina Kroehler, Margaret, Kent State University, mkroehle@kent.edu; Abdul Shakoor, ashakoor@kent.edu; Richard Wooten, rick.wooten@ncdenr.gov; David Korte, david.korte@ncdenr.gov (TS #7) Slope movements significantly impact public welfare by threatening lives and damaging property. In the Blue Ridge Mountains of western North Carolina, catastrophic and major storm systems can trigger hundreds of debris flows and other forms of slope movement. In collaboration with the North Carolina Geologic Survey (NCGS), as part of their landslide hazard mapping program, the North Cove area of McDowell County was selected to determine the relative influence of geologic factors on slope movements in the region. The study area encompassed steep forested slopes in the North Fork Catawba River watershed, which forms a reentrant in the Blue Ridge Escarpment.

Bedrock geology consists of Proterozoic basement gneisses and early Paleozoic metasedimentary rocks. An inventory map of >400 slope movements, and associated deposits, was created by digitally mapping the geomorphic features in ArcGIS using lidar-derived DEM maps, orthophotography, and satellite imagery. Mapped slope movements are roughly half slides and half flows, although many areas are complexes of combined and/or repeated movements. Field investigations were conducted to obtain soil and rock samples for laboratory testing, measure bedrock discontinuities for slope stability analyses, and fieldverify the digital map. The soils within the study area are primarily poorly graded sands and silty sands with low plasticity silt and clay and some gravel. Direct shear tests on soil resulted in friction angles of 36°–43° and cohesion of 261–584 psf, while results for soil-rock contact showed friction angles of 30°–34° and negligible cohesion (<100 psf). Structural analysis from field data (723 measurements) shows the most significant discontinuities are a conjugate pair of near-vertical NE-SW and SE-NW joint sets and low-angle bedding and foliation. A susceptibility map, indicating the influence of bedrock structure and lithology on slope movements, is being prepared.

Carto PMAi – A Project to Evaluate Worker and Public Populations Exposure to Elongate Mineral Particles of Interest Léocat, Erell, OPPBTP, France, erell.leocat@oppbtp.fr; Christine Deneuvillers, christine.deneuvillers@oppbtp.fr; Patrick Richard, patrick.richard@oppbtp.fr (TS #3) The French Ministry of Health, Ministry of Labor, and Ministry of Environment are faced with the emerging issue of cleavage fragment particles with same chemical composition as actinolite asbestos in aggregates used in road pavement. In 2015, the National Agency for Food, Environmental and Occupational Health and Safety (ANSES) published a literature review on the health effect of these non-asbestiform particles. The conclusion is that any study can show the evidence of risk absence related to these particles. After this first report, the French government mandated the National Agency to conduct an expertise on the emission sources of EMPs of interest (EMPi) in the construction industry sector (ANSES, 2017). These particles correspond to the asbestiform and non-asbestiform varieties of the six regulated asbestos minerals and to four other mineral fibers that are recognized to be human carcinogen. The agency recommends leading an exploratory campaign for exploring the potential exposure of workers and general population to EMPi in construction areas. In this context, the three ministries asked in 2017 the Professional Organization for Risk Prevention in Building and Public Work Sector (OPPBTP) 42

to coordinate this campaign. The aim of this “Carto PMAi” project is to provide reliable data based on two protocols to set up legal provisions proportionally to the risk level. First, these protocols have been validated by intercomparison of material and airfield sampling and analyses before being applied in accurate quarries and earthworks in natural environment.

A Machine Learning Algorithm for Rock Mass Characterization and Stability from Point Clouds Li, Echo, Department Mining and Geological Engineering, University of Arizona, jialuoli@email.arizona.edu; John Kemeny, kemeny@email.arizona.edu (TS #7) Three-dimensional technologies are now commonplace for scanning rock masses, and include lidar, photogrammetry, SLAM, and others. Each of these technologies can produce high-resolution three-dimensional point clouds of the rock mass surface. From these point clouds, rock mass characteristics such as discontinuity orientation, spacing, and condition can be extracted. These results can then be used to assess the stability of slopes and underground excavations. If scanning is repeated, then rock mass movement and unstable conditions can be detected. Even though very powerful point cloud programs exist today that can automate many of the processing steps, there is a need for the “smart” assessment of these steps to eliminate erroneous results and increase the accuracy of the final geotechnical risk assessment. An example would include the automated delineation of a set of blasting fractures parallel to a slope face, which can be mislabeled as natural fractures.

Assessing block size and fracture spacing is also very difficult using standard automated procedures. In this paper, machine-learning techniques have been implemented to filter the results from automated point cloud processing routines, as well as estimate parameters that are difficult to determine from these routines. Our approach is to combine automated point cloud algorithms that can produce a good “first draft” of a site’s rock mass characterization, with deep learning algorithms that require training but can mimic the rock mass practitioner’s professional judgement. Because this is an important and complex research topic, we are starting with simple point cloud models of rock masses, including an array of cardboard boxes of different sizes, and progressing to simple point clouds of actual rock masses. Our approach utilizes point cloud algorithms for fracture and edge detection in open-source programs such as CloudCompare, along with deep learning algorithms in Python and Matlab.

Database of Geotechnical Shear-Wave Seismic-Velocity Profile Measurements for California and Nevada Louie, John, Nevada Seismological Laboratory, University of Nevada, Reno, louie@seismo.unr.edu; Alexander R. Simpson, arsimpson@nevada.unr.edu; Jacob Ortega, jacobortega@nevada.unr.edu (Poster) The time-averaged seismic shear-wave velocity from the surface to 30 m (100 ft) depth, defined in the Building Code as Vs30, is in the United States one of the principal determinants of earthquake site-hazard classification. Over the past 20 years, the Nevada Seismological Lab and the Applied Geophysics class at the University of Nevada, Reno, and Optim Earth have made shallow (<1 km deep) shear-wave velocity measurements at 571 sites in Nevada and California, and 40 in New Zealand, using the ReMi technology. The US Geological Survey sponsored many of these measurements, calibrating stations in regional earthquake-monitoring and strong-motion networks. The Google Drive link https://drive.google.com/open?id=15VSI4vhzPfy_GVoB_XYKsWfrhPM9u5E9, also accessible from https://Louie.pub, leads to a directory structure grouping the measurements by region, and the files

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING are often named with a monitoring network station name. Earthquakemonitoring stations are often on bedrock; the database also includes the results of transects across the Reno, Las Vegas, and Los Angeles urban basins that are mostly deep soil sites. Each file is a self-explanatory, plaintext list of the data and results from the measurement. Measurements made at slightly different ReMi array locations, at different times, and by different interpreters produced multiple files for some sites. The multiple results express both the aleatory variation of velocity in the ground, and the epistemic variability of the measurement technique. Each measurement file includes ReMi array-location data, a summary Vs30 value, and a modeled shear-wave-velocityversus-depth profile. Efforts are underway to add the picked ReMi p-f image and the picked fundamental-mode Rayleigh-wave dispersion-curve data to each file. These archives give additional details on ReMi measurements found in the US Geological Survey’s Vs30 archive at https://earthquake.usgs.gov/data/vs30/us/. An additional 10,722 Vs30 measurements in Las Vegas and Clark County, Nevada are available from the Clark County GIS system at http://gisgate.co.clark.nv.us/ow/ (select the “Seismic” map type).

Geologic Hazard Mapping of Mining Communities in Peru Using Remote Sensing and GIS Manning, Justin, Colorado School of Mines Department of Geology and Geological Engineering, just.mann711@gmail.com; Wendy Zhou, wzhou@mines.edu (Poster) Disruption of terrain in the vicinity of mining operations frequently causes geologic hazards, such as landslides, debris flows, and rockfall, which endanger workers and nearby residents. This is especially important in mountainous terrain, such as the Arequipa region in Peru.

Mining operations can lead to increased erosion, changes in hydrological and hydrogeological processes, and can make slopes more susceptible to instability. This exposes new areas and populations to these hazards, thus warranting the geohazard studies of selected mining communities. We aim to develop protocols for multiple geohazard characterizations that can be applied throughout the Arequipa region in Peru. The protocols consist of geohazard inventories, field mapping, and verification, while developing hazard and susceptibility maps through geoprocessing models in a GIS platform. The primary geohazards mapped were landslides, debris flows, rockfall, hillside erosion, flooding, liquefaction, and collapsible soils. For each geohazard, specific criteria were used to rank the hazard levels. For example, a high hazard level for liquefaction requires the geomorphology to consist of recently deposited (Holocene or younger) alluvial material, where the groundwater table is within five meters of the ground surface, and the soil contains less than 5% fines. Meanwhile, a low hazard level for liquefaction requires the geomorphology to consist of recently deposited colluvium, such as debris flow deposits, and alluvium, where the groundwater table is within 15 meters of the ground surface, and the soil contains of 5–10% fines. The result of this process was the creation of hazard maps for each of the geohazards across multiple communities. This work results in improved safety for workers, and for nearby and downstream residents through quantifying mining-induced changes that affect the hazard level of multiple geohazards.

Recent Advances in Stochastic Analyses of Slopes in Bimrocks and Bimsoils Medley, Edmund, edmund.medley@terraphase.com (TS #7)

ence in the mechanical properties of the rock mass at the scales of engineering interest (centimeters to hundreds of meters). Bimrocks include melanges, fault rocks, mega breccias, volcanic complexes, and some weathered rocks. “Bimsoils” are analogous to bimrocks for masses composed of blocks and soil-like matrix (e.g., very weathered rocks, lahars, coarse colluvium, tills). Modest block-matrix strength contrasts force failure surfaces to negotiate tortuously around blocks via weaker block/matrix contacts. Slope stability analyses indicate that tortuous failure surfaces generally produce greater stability relative to matrix-only analyses. Indeed recent studies reveal that there is a penalty (i.e.: lower Factors of Safety) in analyzing bimrocks as having matrix-only conditions. Slopes should always be analyzed taking blocks into account, even if, for low block-proportions and adverse block orientations, less stability is possible compared to matrix-only conditions. Block sizes, block size distributions, block orientations, block shapes, locations of large blocks, and slope geometries are the major influences in the degree of tortuosity and consequent slope stability of slopes underlain by bimrocks and bimsoils. However, the locations and geometry of tortuous failure surfaces at site scales cannot be deterministically predicted so stochastic investigations are preferable. A summary of recent findings of stochastic-based research is presented.

Effect of Multi-stage Failures on Rock Avalanche Mobility: Joffre Peak Case Study Mitchell, Andrew, University of British Columbia, amitchell@eoas.ubc.ca; Scott McDougall, smcdouga@eoas.ubc.ca; Kate E Allstadt, kallstadt@usgs.gov; Brian Menounos, Brian.Menounos@unbc.ca; Tom Millard, Tom.Millard@gov.bc.ca (TS #6) The high mobility of rock avalanches has been the subject of much research. Studies of prehistoric rock avalanches typically assume that failures occurred in a single stage (i.e., en masse), whereas observations of contemporary events suggest that multi-stage (i.e., piecemeal) failures are relatively common. Detailed observations of multi-stage rock avalanches have become available, in which the deposit of one stage was clearly overridden by a subsequent stage, possibly influencing the mobility of the latter stage. One example of a well-documented multistage failure is the Joffre Peak, British Columbia, rock avalanches, which occurred in two distinct stages in May 2019. We use the Joffre Peak case study to test the hypothesis that the deposit of the first stage limited the mobility of the second stage by changing the substrate conditions and path topography. This hypothesis was tested using the Dan3D numerical runout model, with changes in substrate conditions examined using an automated model calibration process which varies the basal resistance parameters to match the observed deposit area and velocity estimates, and changes in topography examined by modelling the second stage with and without the deposit of the first stage present. In conjunction, we use seismic recordings of the two stages to estimate the forces exerted on the Earth during the events. These time series of forcing act as additional constraints on the timing of the initial collapses, subsequent turns, and decelerations of the mass. The modelling results indicate that changes in mobility from one stage to the next in a multi-stage rock avalanche can have important implications for the hazards associated with these events by affecting how far and how fast material travels. Further work is underway to perform calibrations for other study sites to better quantify the uncertainty regarding changes to model parameters resulting from multi-stage failures.

Bimrocks are mixtures of rocks composed of geotechnically significant blocks within a bonded matrix of finer texture. The expression “geotechnically significant blocks” means there is a mechanical contrast between blocks and matrix and that there are enough blocks to make a differSeptember 2020

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING Geophysical Evaluation of Dam Seepage to Support Rehabilitation Efforts

Soil Creep and its Role in Mudslide Generation – Case Study from Erwin, Tennessee

Mundell, John, Mundell & Associates, Inc., jmundell@MundellAssociates.com; Ryan Brumbaugh, RBrumbaugh@MundellAssociates.com; Forrest Kunkel, FKunkel@MundellAssociates.com (TS #5)

Nandi, Arpita, East Tennessee state University, nandi@etsu.edu; Mick Whitelaw, WHITELAW@mail.etsu.edu; Sarah Harris, HARRISSL1@mail.etsu.edu; William Tollefson, TOLLEFSON@mail.etsu.edu (TS #7)

Active seepage and erosion of an earthen dam in western Kentucky raised concerns about the integrity of the dam and threatened a town’s drinking water supply. Initial grout injections to stop the seepage proved ineffective; therefore, the water level of the reservoir was lowered to prevent possible failure due to piping of soil materials. In order to characterize the internal dam and foundation conditions and to provide guidance on possible remedies and/or subsequent additional investigation with borings, a geophysical survey was conducted along the 1,200-ft-long earthen dam. The geophysical survey techniques included the completion of electromagnetic (EM) terrain conductivity mapping, 2D electrical resistivity imaging (2D-ERI), Self-Potential (SP) profiling and Ground Penetrating Radar (GPR). This multi-phased geophysical approach was chosen due to the lack of previous soil boring and geotechnical engineering testing data and ultimately provided a robust method for identifying the locations of seepage zones in the unconsolidated dam embankment and underlying bedrock.

This study investigates soil creep and its potential role in mudslide generation, after heavy rainfall, on an Appalachian hillslope. The slope is located on the east face of Looking Glass Mountain, Erwin, East Tennessee. It consists of a 1.5–3.0-m-thick clayey sand and gravel soil which overlies well bedded Cambrian dolomites, and the Buffalo Mountain thrust, both oriented subparallel to the hillslope. The slope has failed twice in the past two years along the soil-bedrock contact. Slope movement was measured bi-weekly from June 8, 2019 to March 8, 2020 using 13 steel-pinned targets and a laser range finder. Rainfall data were collected from three weather stations in the vicinity. Three digital elevation models (DEMs)—one from lidar data taken in 2018 and two UAV generated, one before and one after an April 13, 2020 mudslide event—were used to evaluate the affected area, volume of displaced material, and head scarp regression from the mudslide toe.

The average rate of soil creep was 0.129 m/year. Soil creep during the study period positively correlated with rainfall accumulation (r = 0.56, p < 0.05). The soil creep was twice interrupted by sudden mudslides, on April 19, 2019 and April 13, 2020, after 6.73 cm/day and 8.74 cm/day high intensity rainfall events, affecting areas of 273.30 m2 and 484.23 m2, respectively. Approximately 844 m3 of soil was displaced and the head scarp regressed 11.22 m during the 2019–2020 monitoring period, which captured the April 2020 mudslide event. Additional DEM evaluation indicates the presence of a break in slope further up the hill, possibly due to continuous soil creep, which could develop as a head scarp in the future. This study suggests that soil creep might play an important role in slope destabilization and produce mudslides after heavy rainfall.

Calibrating Artificial Intelligence and Hydrologic Modeling with Smart Monitoring Inputs for Enhanced Levee Safety Predictions Under Changing Climate Conditions Mundell, John, Mundell & Associates, Inc., jmundell@MundellAssociates.com; Tyler Balson, TBalson@MundellAssociates.com; Luke J. Johnstone, LJohnstone@mundellassociates.com; Forrest Kunkel, FKunkel@MundellAssociates.com (TS #8) Monitoring the integrity of levee systems is paramount to ensure longterm functionality and continued protection of critical infrastructure. In our current state of non-stationary climate changes, these levee systems are being subjected to harsher and more frequent stressors.

Traditional mechanistic hydraulic models used to evaluate underseepage often require complicated mathematics, detailed subsurface characterization over large areas, and are computationally challenging.

Additionally, it is still relatively unknown how some of these models will perform under extreme weather scenarios. As real-time monitoring and sensing equipment gain popularity, and the economics of implementation become more feasible, unique opportunities emerge to apply state-of-the-science Artificial Intelligence (AI) and Machine Learning algorithms to the performance evaluation of levee systems. Unfortunately, the predictions of these data-driven models are still fraught with some skepticism. In order to leverage the strengths of both datadriven and mechanistic modeling, this presentation will summarize the results of a recent levee seepage study that developed both model types independently and compared their calibrated results. This assessment demonstrates one of the first quantitative evaluations of this type of application and gives some insight into how future levee system evaluation may be performed, utilizing an increase in smart monitoring data collection as one tool to improve the predictions made for changing climate conditions.

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How Training and Education in Radon Mitigation Has Provided Invaluable Insights for Vapor Mitigation: Supported by Three Case Studies Noyes, John, CABENO Environmental Field Services, LLC, john.noyes@cabenoenvironmental.com (TS #2) In order to get out in front of draft Vapor Intrusion Guidance released in Illinois in 2011, CABENO Environmental Field Services, LLC (CABENO) turned to the radon industry. The goal was not just to learn soil gas sampling methodologies but to also understand the mechanisms by which soil gas moves into buildings and the methods used for mitigation. At the time, the radon industry was the most technically proficient and experienced with the mechanisms of soil gas movement. The radon industry offered the necessary education and training for radon/soil gas/soil vapor mitigation and had the most experience with challenging remediation projects. The American Association of Radon Scientists and Technologists (AARST) is a nonprofit trade organization that hosts a comprehensive annual event that brings together public officials and scientists, researchers, and service professionals in the radon industry. AARST symposia provided invaluable training for CABENO. Most useful was the opportunity to learn from real world experiences shared by other professionals in the radon industry. This training has been crucial to CABENO’s success within the radon and vapor mitigation industry. Three residential case studies will be presented that illustrate CABENO’s successful completion of vapor mitigation projects.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING Change of Bakken Shale Stiffness Due to CO2 Saturation Ogochukwu, Ozotta, University of North Dakota, ogochukwu.ozotta@und.edu; Mehdi Ostadhassan, mehdi.ostadhassan@gmail.com; Kouqi Liu, liu3k@cmich.edu (Poster) Middle-Bakken is a heterogeneous material with complex microstructures, lithofacies and mineralogical composition. To evaluate the mechanical properties of the rock material and the volume fraction, mineral composition is a critical factor because rock brittleness index increases with increase of the brittle mineral content in the rock with minerals like calcite, sulfur, and zinc-blend. Major minerals present in the Middle-Bakken include clay, calcite, quartz, dolomite, and feldspar.

Minerals present in the Middle-Bakken sample at the depth of investigation are calcite, quartz, dolomite, plagioclase, pyrite, and halite. Calcite dissolution is more common in carbonate-rich rock and it increases the brittleness of the rock and makes it susceptible to fracture, whereas precipitation of clay minerals as calcite dissolves make the rock more ductile and susceptible to deformation. The minerals present were estimated from the Field Emission Scanning Electron Microscope (FE-SEM) image. The sample was exposure to CO2 for up to 60 days and the elastic properties of the mineral grains in the Middle-Bakken was measured using nanoindenation testing. Statistical Approach was used to interpret the changes in the mechanical properties of the mineral grains and the changes in the volume fraction of the minerals before and after CO2 saturation, and general decrease greater than 40% was observed. Frequency distribution showed the volume concentration of the minerals based on their elastic properties as it changes from pre-saturation to post-saturation. Discrete distribution map was used to visualize the spatial distribution of the individual mineral grains present in the rock. The discrete distribution map shows the elastic modulus and hardness of the shale reservoir for CO2 pre-saturation and for post-saturation periods. A heterogeneous distribution of both mechanical properties in the shale reservoir was observed. The images roughly display the microstructure morphology of tested area and then indicate the approximate surface fraction of different constituent phases.

Investigating Risks Related to Unstable Slopes in Great Smoky Mountains National Park O’Shea, Thomas, East Tennessee State University, OSHEAT@mail.etsu.edu; Samantha Farmer; Arpita Nandi Rockfalls are frequent events in the Southern Appalachians, United States, initiated in highly weathered, fractured metasedimentary rocks.

In this study, the Unstable Slope Management Program for Federal Land Management Agencies (USMP for FLMA) protocols were utilized to create an inventory of unstable slopes and evaluate their current hazard and risk conditions along the paved transportation corridors in Great Smoky Mountains National Park (GRSM). Kernel Density Estimations (KDE) and weighted overlay analyses were used to identify clusters of unstable slopes along transportation corridors and select sites for detailed rockfall and environmental impact assessments. A total of 253 unstable slopes were studied along 186 miles of roadway, of which 223 slopes were designated as localized rockfall, dominated by wedge and planar failure mechanisms. Five clusters concentrated along primary roads were identified by KDE, which used the USMP for FLMA risk and hazard values as the intensity fields. Weighted overlay analysis was then used as an intermediate step to refine site selection.

Six variables were used in the weighted overlay analysis: KDE raster layers, slope, distance to map-scale faulting, distance to roadway, and the predicted acid-producing potential of geologic units. Based on the results of the weighted overlay analysis, seven sites were selected for detailed site assessments, which will include rockfall simulations and September 2020

acid-base accounting. The research provides a case study on how to prioritize areas for site-specific investigations with the ultimate aim to improve safety for GRSM visitors and commuters.

Behavior of the Chagrin Shale in Selected Tunneled Excavations, Cleveland, Ohio Piepenburg, Michael, Mott MacDonald, michael.piepenburg@mottmac.com (TS #1) Numerous tunnels ranging in size from 3.5–28 feet in excavated diameter have been successfully completed with a variety of excavation methods in the Chagrin Shale located below northeastern Cleveland Ohio. The medium strong shale is comprised of thin horizontal beds of clay-rich shale with joints typically <25 feet in length and spaced at 2–2.5-ft intervals. Groundwater inflow, swelling, and stress relief in the shale are uncommon occurrences in excavations; desiccation of the shale caused by wet-dry cycles and gas inflows are more common and problematic underground construction related issues. Reduction of ground loss and the tunnel shape in the crown and arches is largely due to a loss of confinement across the shale’s horizontal partings; as a result, time limits and distances that the newly excavated ground may remain unsupported have been established in the local tunnel design community. Three examples from tunnels excavated by different methods are presented to illustrate the rock mass stability-related issues in the Chagrin Shale.

Reaching New Heights: The Cascade Volcanoes as Exemplary Laboratories for Applied Geoscience Pope, Isaac, Centralia College, isaac.pope@student.centralia.edu (TS #4) Towering along the Cascade Magmatic Arc, the Cascade Volcanoes are a series of quaternary composite cones that attest to the varied history of this dynamic landscape. That history, a continuation of the volcanism that has dominated the region since its commencement in the Eocene, indicates the presence of several types of geological hazards in the area. This dynamic environment thus provides the motivation for, as well as an unparalleled laboratory for, a variety of fields of geologic investigation, of which physical volcanology is only the most obvious. The numerous glaciers that occur on the flanks of the cones allow glaciologists to study not only glacier dynamics but also the glacial responses to volcanic activity and a fluctuating climate.

Mass wasting events, which pose hazards across the United States, may be similarly studied either as direct results of volcanic activity or indirectly through geomorphic evolution in the high topographic relief of the Cascade Magmatic Arc. The ensuing fluvial geomorphology from glacial meltwater and the humid Mediterranean climate of the region has stimulated several investigations of stream progression in a variety of energy regimes, such as during glacial meltwater floods (jökulhlaups). Sedimentary deposits resulting from these diverse processes can be studied in the field both during and following their formation, providing geologists with invaluable tools for identifying volcanic hazards to the adjoining valleys. Knowledge of hydrogeology may also be advanced through study of groundwater flow in the varied lithologies and structural elements of the region, particularly focusing on fracture permeability. The very nature of the dynamic Cascade Volcanoes provides an exemplary laboratory for advancing geologic knowledge of these “crucibles of change.”

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AEG 2020 VIRTUAL ANNUAL MEETING Poorly Sorted Terrace Deposits of the Cispus Valley: Glacial Drift or Mount Adams Lahar?

Pope, Isaac, Centralia College, isaac.pope@student.centralia.edu (Poster) Incising through folded Oligocene basaltic andesite bedrock, the Cispus River meanders along the western slopes of Mount Adams before flowing westward towards Mayfield Lake near Randle, Washington. A veneer of tephra dated 1.2 ka from Mount St. Helens covers the Cispus River terraces and adjoining hills, attesting to recent manifestation of volcanism in the region. Despite this valley being classified as high-risk for lahars from Mount Adams, little research has been done to identify any previous lahars along the drainage. Examination of the Cispus River terraces reveals imbricated, poorly sorted, reverse graded deposits typical of debris flows. These deposits are found along multiple terrace levels and are sedimentologically similar, while clast lithologies indicate a provenance to the east. The 30-meter elevation difference between the lowest terrace and the surface of the highest terrace denotes the minimum flow depth; it is here estimated that the lahar was 0.3 cubic kilometers. Clasts within the debris flow deposits are often andesites and volcaniclastics distinct from the local basaltic andesite bedrock.

Coupled with the eastward dipping imbrication, the clast lithologies suggest a provenance to the east near Mount Adams. While the pumiceous tephra (1.2 ka) that blankets the region provides the minimum age, the poorly sorted terrace deposits have been previously dated as approximately 20 ka, which is based on the interpretation that the deposits are glacial drift. If these deposits are instead laharic in origin, however, the lack of overlying till or drift suggests a younger, late-glacial age of the lahar. This age correlates nicely to the latest series of Mount Adams eruptions from 40 ka to 10 ka during which time the present edifice of Mount Adams was produced. This lahar may be among the largest and oldest lahars yet identified from Mount Adams.

Tree-Ring Analysis (Dendrochronology), a Tool for Dating of Subfossil Forests – Victim Tree Examples from Mount Rainier Lahars and the Bonneville Landslide Pringle, Patrick T., Science Department, Centralia College, patrick.pringle@centralia.edu (TS #4) Bark-bearing old-growth tree victims of past earthquakes, landslides, and volcanic eruptions and lahars allow wiggle-matching of radiocarbon dates and higher precision ages, which helps narrow the focus of treering cross correlations. Examples from Mount Rainier from the past 1,600 years include trees buried near Kent, Washington (~518–550 CE), at Fife and Auburn (~900 CE), and by the Electron Mudflow in the Puyallup River Valley (~1490–1510 CE). Wood samples obtained with borers and saws were mounted, polished, and scanned at 0.01mm resolution. ImageJ software was used for tree-ring measuring, and programs Cofecha and Arstan for analysis along with visual examination and cross-dating methods, such as noting narrow rings and low-density “light rings.” At Kent we cross-correlated five Douglas fir (Pseudotsuga menziesii); three displayed minor earlywood beneath bark, suggesting tree death in spring (Moran et al, 2017). The Fife subfossil trees include sub-horizontal logs at ~3–4 m depth and one standing Western red cedar (Thuja plicata) rooted at a depth of ~5 m. Trees of that age at Auburn had been buried by an eruption-triggered lahar that appears to correlate with deposits at the Port of Seattle and those in Fife. Radiocarbon ages of the trees in Fife and Auburn are similar to dates on trees killed by the Seattle Fault (Atwater, 1999) and Tacoma Fault (Sherrod and others, 2004). Trees killed by the Electron Mudflow include 28 Douglas firs recovered near Orting and from Lake Kapowsin, which was dammed by the Electron Mudflow. A long (341 years) tree-ring

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chronology derived from eight Electron trees can be used to cross-date tree victims of the mid-1400s Bonneville landslide in the Columbia River gorge 133 km to the south. Oral stories of the indigenous peoples appear to describe lahar events at ~900 CE, the Electron Mudflow (Kearns and Pringle, 2015), and the Bonneville landslide.

Use of Close-range Photogrammetry to Generate 3D Models of Drill Core Reimers, Carson, South Dakota School of Mines and Technology, carson.reimers@mines.sdsmt.edu; Kurt Katzenstein, kurt.katzenstein@sdsmt.edu; William Roggenthen, william.roggenthen@sdsmt.edu (Poster) Most subsurface investigations in rock related to geological, geotechnical, and petrophysical projects involve the costly and time-consuming process of drilling and collecting rock core specimens. These specimens provide an excellent record of physical and chemical properties that can be used to assess lithology, geologic structure, geomechanical, and fracture characteristics, as well as provide the ability to measure petrophysical and geophysical properties. However, often observations are collected by a single individual on field logs with a specific focus related to the project at hand, often under duress due to time constraints related to the rate of drilling and/or poor weather conditions. Once fieldwork is completed, the core is placed into boxes, often having to be broken to fit and transported to either a permanent or temporary repository for storage. The process of transporting the core often damages it, particularly in the case of weak or friable rock. Upon completion of the project for which the core was collected, samples are often discarded, making future utilization of the core impossible. These realities limit the data acquired and sample accessibility. Thus, the present research aims to develop a methodology to acquire imagery of core in the field for the purpose of generating three-dimensional, spatially referenced photogrammetric models of drill core with the use of AgisoftTM, a readily available commercial software package. These models can be viewed, shared, and archived indefinitely, which will allow for more investigations to utilize data from the core during the project or even long after the completion of the project. Furthermore, the high-resolution spatially referenced 3D core models could be used as a “base map” for other data collected from the core or the core hole so that ancillary data could be tied directly to the core itself, allowing for a much more informative, accurate and detailed analysis.

Rock Quality Characterization Using Blast Hole Penetration Rate Data USACE Isabella Lake Dam Safety Modification Project Kern County, California Riley, Donald B., Flatiron Construction Corp, ddam.riley@gmail.com; Don Terres, dterrestrialsi@gmail.com; Tom Devine, tdevine1@nmggeotech.com; William Godwin, Bgodwin@Kleinfelder.com; James Martin, F.James.Martin@usace.army.mil (TS #8) The USACE Isabella Lake Dam Safety Modification project is located in the Southern Sierra Nevada Mountain Range, approximately 40 miles northeast of Bakersfield, California. Two existing dams and a service spillway at the site were originally constructed along the Kern River in the early 1950s. These structures are currently being renovated in order to address seismic, hydrologic and seepage concerns. In addition, a new emergency spillway is currently being constructed. Rock being quarried during drill and blast operations at the emergency spillway is utilized to produce different sized end products for placement within various zones of the existing dams that are being raised

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING as part of the work. Foundation rock at the emergency spillway area is mainly composed of granite, tonalite and aplite. Interpretation of penetration rate data, obtained during tophammer percussion drilling of blast holes, aids in the generalized characterization of rock quality and other subsurface conditions for each production blast. Rock quality is divided into three categories: highly weathered (C rock), moderately weathered (B rock) and slightly weathered to fresh (A rock). Blast holes are typically 3.0–3.5 inches in diameter and range from 10–45 feet in depth. Geologic data obtained during mapping of walls exposed after muck pile removal are integrated with blast hole penetration rate data to create rock quality/geo maps for each production blast. These maps help delineate weathering zones and identify prominent joint sets or structural trends within the rock mass that could impact blasting operations. The interpretative maps are provided to various project personnel prior to each blast for purposes that include: volume estimation of rock quality, blast planning and coordination of mucking and hauling operations. Generalized criteria developed to evaluate and estimate rock quality will be discussed. Illustrations characterizing generalized rock quality and geologic conditions at the Emergency Spillway will be presented.

Prevention and Recording of a Large Landslide Event Using Ground-Based Interferometric Radar at Roberts Mountain, Oregon Robinson, Rory, Oregon Department of Transportation, Tony.Robinson@odot.state.or.us; Pete Castro, Pete.T.CASTRO@odot.state.or.us; Jill DeKoekkoek, Jill.DeKoekkoek@odot.state.or.us; Philip Wurst, Philip.WURST@odot.state.or.us; Michael Tardif, Michael.W.TARDIF@odot.state.or.us; Brian McMullen, Brian.MCMULLEN@odot.state.or.us; Bryce Rogers, Bryce.W.ROGERS@odot.state.or.us (TS #6) An ongoing Oregon Department of Transportation project along Interstate-5, located south of Roseburg at Roberts Mountain, is intended to add additional climbing lanes by widening the freeway. Widening near the summit required reconfiguration of an approximately 90-m-ong buttress at the base of an older landslide. Geology within the project site is entirely within the Dothan Formation, which is a mélange of relatively weak blocks in a highly sheared matrix. Realignment of the buttress called for short sections to be removed and replaced into the new buttress configuration. After beginning construction, slope inclinometers indicated increasing movement and the lead geotechnical engineer implemented a risk management program. IDS GeoRadar began monitoring the site using ground and satellite based radar. On October 4, 2019, shortly after ground radar installation, movement above the first buttress slot-cut began to accelerate. Over a five-day period with work on the buttress continuing, peak surface ground movement velocities, as measured by the radar system, increased from 29 to as much as 68 mm/day. Seeing that the movement was accelerating, ODOT’s Construction Office worked with the Project Contractor to halt work and quickly backfill the slot excavation. Radar velocities were corroborated with in-ground Micro-Electro-Mechanical-Systems (MEMS) arrays located within exploratory borings which penetrated the landslide mass. This initial movement encompassed a mass in the toe area approximately 74m wide by 45m tall. Over subsequent months, active movement progressed up to the original headscarp and widened the lateral limits by an additional 15m. The radar system captured additional movement as a series of smaller blocks shifting downslope to rest against the initial mass. The individual radar images have been combined to produce a video, which provides an animated illustration of how this coalescing landslide behaved.

September 2020

US Highway 20, between Pioneer Mountain and Eddyville, Oregon: The Observational Design Approach, Now Post-Construction Robinson, Rory, Oregon Department of Transportation, tony.robinson@odot.state.or.us; Michael Tardif, Michael.W.TARDIF@odot.state.or.us; Larry Robinson, Larry.ROBINSON@odot.state.or.us (TS #6) Circa 2012, an approximately 3.5-mile section of US highway 20, between Pioneer Mountain and Eddyville, Oregon, was realigned during construction to mitigate the effects of several large deepseated landslides at a total cost that approached $500 million (2016 dollars). The Observational Design Approach (i.e. Method) was utilized during this process as it was recognized that it was simply not feasible to stabilize bridges on landslides and simultaneously satisfy seismic design criteria for structures. This “Observational Method” can be defined as a continuous, managed and integrated process of design, construction control, monitoring and review enabling appropriate, previously-defined modifications to be incorporated during (or after) construction. For this project, this method utilized contemporaneous measurements of ground deformation coupled with groundwater measurements to provide feedback during the design and construction stages. Landslide and rockslide stability at the project site was and still is significantly affected by groundwater and surface water impacts. This was evidenced by seasonal variations in slide movement and catastrophic slide failures during intense rainfall events. Therefore, a significant part of the landslide mitigation was intended to improve control of surface water and reduce overall groundwater levels by the installation of subsurface drains, including both crushed rock sub-drains and nearly 110 miles of drilled horizontal drains. Now, post-construction monitoring of the in-ground sensory network continues on an annual basis. Overall, the project has been performing within allowable deflection tolerances. We have determined that at a minimum, the monitoring program needs to continue through a variety of seasonal climatic conditions to document the effectiveness of the design. Additionally, the monitoring program needs to continue through at least one or two complete maintenance cycles for the horizontal drains, to document the effectiveness of both the reconditioning/cleaning effort as well as the assumed 10-year cleaning interval.

Site Characterization of Levee Foundations Rogers, J. David, Department of Geosciences and Geological Engineering, Missouri University of Science & Technology, rogersda@mst.edu (TS #8) Between 1986–2005 the speaker served as the principal engineering geologist representing 1,500+ victims of a levee break along the lower Yuba River in February 1986. The breach inundated the towns of Linda and Olivehurst, California. Forensic work included developing an extensive historical database, chronicling circumstances surrounding past levee failures, seeking to understand the geomorphic processes shaping the channel, and reviewing excavation permits and maintenance activities by the local reclamation district. Detailed stratigraphic correlations were carried out across the area and a working model emerged which predicted levee failure at the precise location and within the timing parameters that were observed. The case was in litigation for over 19 years and led to a landmark decision by the California District Court of Appeal in 2003. The California Supreme Court refused to review the decision in 2005. The decision resulted in the State being found liable for failure of a flood control project to function as intended by applying a constitutional balancing test that weighed the benefits provided by the project against the gravity of the harm caused. This resulted in a finding of unreasonable conduct

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AEG 2020 VIRTUAL ANNUAL MEETING that if left uncompensated, would require plaintiffs to bear more than their fair share of the costs of the public project. The decision and the damage suffered by New Orleans in Hurricane Katrina in 2005 triggered a new era of risk-based assessment of levee hazards. This has resulted in detailed evaluations of existing levees and retrofitting to bring critical levees up to modern safety standards.

Environmental and Geologic Hazards near Small-Scale Gold Mines in Peru: An Analog for 19th and Early 20th Century Mining in Colorado Santi, Paul, Colorado School of Mines, psanti@mines.edu; Aaron Malone, amalone@mines.edu; Nicole Smith, nmsmith@mines.edu; Josh Sharp, jsharp@mines.edu; Justin Manning, jtmanning@mymail.mines.edu; Wendy Zhou, wzhou@mines.edu; Pablo Meza, pmezaa@unsa.edu.pe; Percy Colque, scolquer@unsa.edu.pe (TS #6) Artisanal and small-scale (ASM) gold mines in Peru share many characteristics with 19th century gold mining in Colorado and the western US. This offers us a backward look into environmental issues during mining in the past, and conversely can provide a forward look into future environmental conditions at locations currently being mined in similar ways. Understanding the connections between the two locations and times and the evolution of ASM in the US will enhance sustainable development of ASM in Peru and elsewhere. While some scale-scale gold mines in Peru operate with modern technologies and with environmental protections in place, many employ more rudimentary mining and mineral processing methods with very little adherence to environmental controls. This is reminiscent of older methodologies employed during the gold rush in the western US. Like early mining in the western US, work is done by smaller enterprises or within smaller communities, production can take precedence over safety and environmental protection, and governmental regulation is either missing or less rigorously followed or enforced. Both locations have high potential for metal and acid loading in receiving waters, significant landscape disruption and erosion, and associated environmental and biota impacts. Both locations are subject to similar geologic hazards, some of which are exacerbated by mining and its accompanying population growth, such as rockfall, debris flows, landslides, erosion, adverse soil behavior, flooding, and in the case of Peru, seismic and volcanic hazards. Finally, both locations are subject to significant inmigration of miners and rapid population growth, creating tension or conflict with previous residents and land-uses, and lowering awareness of local geologic hazards and changing the viable options for reducing risk and protecting the environment.

Construction, Operation, and Failure of Ka Loko Dam, Kauai, Hawaii Shaller, Philip J., Engineering Systems, Inc., pjshaller@engsys.com; Macan Doroudian, mdoroudian@engsys.com; Kristina Cydzik, kcydzik@engsys.com; Parmeshwar L. Shrestha, plshrestha@engysy.com (TS #5) The Ka Loko dam failure highlights the risks of aging, repurposed infrastructure and accelerated weathering in a warm tropical climate. The dam lies in the wet northeastern quadrant of Kauai at 750 feet elevation. Constructed circa 1890 to provide reliable water for sugar cane cultivation, it was built using hydraulic fill methods and later raised by addition of a non-hydraulic fill cap. The dam occupied a gap in the wall of a late-stage Koloa volcanic series crater formed by an ancient sector failure corresponding with a volcanic debris flow traceable to the modern coastline. The dam stands atop heavily weathered, weak, layered, reworked, volcanic ash deposits (saprolite). The reservoir has 48

a small natural watershed and is therefore fed almost entirely by manmade ditches. For most of its operational lifetime, dedicated plantation staff managed the ditches and reservoir water levels. Circa 1970, the sugar plantation ceased operation, after which a small private water company took over reservoir operations. A severe drought in late 2005 drastically lowered reservoir levels. When heavy rains returned in early 2006, the feeder ditches remained open to replenish water levels. The refilled dam, standing just below full pool, failed in the early morning hours of March 14, 2006, three days after cessation of the heavy rainfall. The sudden failure released about 320 million gallons of impounded water, overtopped a downstream dam, caused seven deaths, and resulted in significant property damage. A subsequent forensic investigation concluded that the breach resulted from a sliding failure in the volcanic substrate, which had suffered extreme chemical alteration as a result of decades of interaction with oxygen-depleted seepage from the bottom of the reservoir. Analogous to the weakening of a steel beam by oxidative corrosion, this anoxic weathering process progressively transformed the volcanics into nearly pure, fine, weak, sensitive, halloysite clay.

An Investigation and Comparison of Stable Isotopes in Meteoric Waters and Groundwaters from Southern Washington Smoot, Emily, Portland State University, esmoot@pdx.edu (Poster) A main source of freshwater in the Pacific Northwest is the Columbia River Basalt Group aquifer system. The semi-arid region of eastern Washington has undergone heavy groundwater depletion in recent decades due to increasing population and expanding agricultural use.

Aggressive mining has resulted in drawdowns of up to 30 meters. By using stable isotopes oxygen-eighteen (18O) and deuterium (D), this study confines the timing of groundwater precipitation and proposes an explanation for why drawdowns are so significant. The isotopic composition of meteoric water is compared to groundwaters from southeast Washington. The two populations are statistically different (p < 0.001, alpha = 0.05). The isotopic composition of groundwaters from the deepest wells (< -150 m msl) are isotopically lighter than meteoric waters and not achievable by recharge under the current climate. These deep groundwaters are interpreted to have precipitated during the Last Glacial Maximum in the late Pleistocene and finished precipitating roughly 5 ka. Thus, replenishment of the aquifer cannot be expected to keep pace with extraction. Additionally, this research examines the elevation response in the stable isotope signature of meteoric water along the 47° N latitude by computing three lapse rates for 18O for the windward and leeward sides of the Cascade Range. The windward lapse rates are -6.4 ‰/km (R2 = 0.72) for elevations below 1,300 meters (amsl), and -2.5 ‰/km (R2 = 0.88) for elevations above 1,300 meters (amsl). The leeward lapse rate is 12.9 ‰/km (R2 = 0.70), suggesting minimal air mass mixing over the Cascade Range during transport.

Preparing for The Big One: Data-Driven Spatio-Temporal Risk Maps for Earthquake Evacuation in L.A. County Sosa, Jacqueline, Spatial Sciences Institute, University of Southern California, jacqueds@usc.edu; Orhun Aydin, oaydin@usc.edu (TS #7) A recent study by the United States Geological Survey (USGS) shows that a portion of the San Andreas Fault close to Los Angeles could be overdue for a major earthquake. Under such circumstance, it is vital for Los Angeles County to be prepared to enable safe and manageable evacuation. An efficient evacuation plan helps citizens and government workers make appropriate decisions when preparing, responding, and taking precautions before and during an earthquake.

Past studies focus on population density as an essential part of

AEG 2020 Virtual Annual Meeting – Program with Abstracts

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AEG 2020 VIRTUAL ANNUAL MEETING understanding, which areas are at a higher risk in the event of an earthquake. However, most studies fail to consider the dynamics of population density at different times of the day. The areas that are densely populated during a weekday are not the same areas that are densely populated on weekends. In addition, metropolitan areas show great fluctuation of population density during work hours. Thus, a sophisticated evacuation plan needs to consider the space-time patterns of population density. This study focuses on creating risk surfaces that indicate which areas in LA pose the major threat because of high population during different days of the week and different hours of the day. First, it separates places depending on when they are most frequently visited. For example, attractions, like shopping centers, are mostly visited during the weekends and places of work, like business headquarters, are mostly visited during the weekdays. Subsequently, this study derives data-driven spatio-temporal risk maps that model areas and times evacuation can be cumbersome. We define a space-time density-based clustering method to model fluctuations in population density clusters. Finally, we define the risk layers as a function of resistance to evacuation and hardship of population dispersion.

Permafrost Thaw, Precipitation, and the Pretty Rocks Slump – A Climate Change Induced Landslide in Denali National Park?

Stanczyk, Anna, Golder Associates, Inc., anna_stanczyk@golder.com; Denny M. Capps, denny_capps@nps.gov; Douglas A. Anderson, douglas.a.anderson@dot.gov (TS #6) Between 2015 and 2016, the Pretty Rocks Slump caused 0.8 m of subsidence over a 100-m length of the Denali National Park Road.

Since 2016, the downslope movement rate has accelerated. This study seeks to characterize the ground movement, including its geologic setting and composition, areal extent, and, possible failure mode and driving forces. The investigation is primarily surficial, although, some limited subsurface data are incorporated. The landslide is situated on a steeply dipping wedge contact between highly altered, fractured basalt (dike) and rhyolites of the Teklanika Formation.

Clays with coarser sediments were sampled throughout the landslide body. Subsurface information (borings and geophysical surveys) indicates that appreciable ice-rich permafrost is present below the road surface. The 2018 measurements show the permafrost is nearly 0° Celsius and, therefore, is likely thawing. This permafrost thaw accords with regional trends. The active landslide limits are defined by a subtle, undulatory headscarp above the road, distinct lateral scarps with vertical displacement across the road, and three well-defined toe features below the road. The 2015–2016 annual rate of landslide movement (0.8 m) has increased to 3.7 m according to 2018 test boring measurements. We suggest a correlation between increased temperature, precipitation, and ground movement based upon local climate data. In 2016, we defined the Pretty Rocks Slump as an earthflow using the updated Hungr and Varnes classification system, attributing landslide movement to steep topography, weak underlying clays, thawing permafrost, and poor drainage. However, continued observations suggest the ground movement may be consistent with a rock glacier. The 2016 study lays the foundation for understanding the limits and possible causes of the Pretty Rocks ground movement as the National Park Service continues to evaluate road mitigation options.

September 2020

Introduction to the Session on Applied Geoscience Methods for Problem Solving Stirewalt, Gerry L., US Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Engineering and External Hazards, gerry.stirewalt@nrc.gov; David F. Fenster, rockpic001@gmail.com (TS #4) A variety of topics related to use of applied geoscientific methods for problem solving, rather than a primary single technical focus such as a symposium might have, will be presented in this session. Presenters include students, academicians, consultants, industry representatives, and Federal employees who will take us to a variety of national and international geographic locations for discussions that will cover such topics as evaluation of potential hazards in volcanic terranes, location of abandoned mine tunnels, assessing potential hazards for selection of natural areas, evaluation of unstable slopes, use of remote sensing techniques for evaluating permafrost degradation, a new method to mitigate earthquake-induced liquefaction, tree ring correlation for matching radiocarbon dates and higher precision ages, and developing spatio-temporal risk maps for earthquake evacuation. Although the technical topics are distinctively different, the presentations will showcase how a broad spectrum of geoscientific methods have been practically applied to creatively and innovatively address the following key factors that form a common thread for all presentations in the session: 1) identify and evaluate the potential problem of concern, 2) collect and evaluate data pertinent to the problem, 3) propose and discuss potential solutions to the problem, and 4) clearly communicate the basis for the proposed solution. These primary factors, whether explicitly considered by practitioners or not, are essential components for successful application of geoscientific methods to the solution of geoengineering and environmental problems.

Radon-222 Occurrence in Groundwater is Highest in Appalachian Piedmont, Eastern USA and Correlates to Lead-210 Occurrence Szabo, Zoltan, New Jersey Water Science Center, US Geological Survey, zszabo@usgs.gov (TS #2) For radon-222 in drinking water, the US Environmental Protection Agency (USEPA) proposed a 300-pCi/L (picocuries per liter) Maximum Contaminant Level (MCL) and a 4,000-pCi/L Alternate MCL (AMCL), for which timely mitigation is recommended. Radon-222 groundwateroccurrence and geological maps may be coupled to identify where risk reduction may be maximized. Groundwater radon-222 concentrations are related primarily to uranium abundance in aquifer materials, though porosity and emanation are important. Regional surveys by the US Geological Survey have characterized radon-222 groundwater occurrence by geological province. In the eastern USA, radon-222 concentrations greater than (>) 4,000 pCi/L were much more frequent in the Appalachian Piedmont Province (PIED) than in other physiographic provinces. Concentrations exceeded 4,000 pCi/L for radon-222 in 19–29% of the samples from various surveys from the PIED, and about 90% had concentrations >300 pCi/L. Many PIED lithologies had similar mean-rank and median radon-222 concentrations (1,000-2,000 pCi/L). Only mafic lithologies had low radon-222 concentrations (median, about 240 pCi/L). The highest median concentrations (about 3,600 pCi/L) were for granites and schist-rock-aquifers. Nearly all radon-222 concentrations >10,000 pCi/L were from granites; some were from biotite gneiss. Assessing groundwater for concentrations of lead-210 (progeny of radon-222) may be prioritized for PIED wells with radon-222 concentrations >4000 pCi/L. Of 60 PIED public-supply wells surveyed, 23 percent had high lead-210 concentrations (>1.0 pCi/L, the level considered a human-health benchmark on the basis of

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AEG 2020 VIRTUAL ANNUAL MEETING USEPA-computed cancer risk), including in 72% of samples with radon222 concentrations >4,000 pCi/L. The concentrations were strongly correlated (+0.712). In Coastal Plain sediment-aquifer surveys, about 19 to 22 percent of samples had radon-222 concentrations >300 pCi/L (range of medians, 140–240 pCi/L; about 3.5 percent had concentrations >1,000 pCi/L). High lead-210, found in 3% (of 348 samples), was associated with anoxic conditions. High concentrations of lead-210 were not correlated with those of radon-222 in the Coastal Plains, unlike the correlation observed in the Piedmont.

Permafrost Degradation as Geological Engineering Challenge in Alaska: Application of Remote Sensing Techniques Tcibulnikova, Iuliia, Department of Geological and Mining Engineering and Sciences, Michigan Technological University, itcibuln@mtu.edu; Thomas Oommen, toommen@mtu.edu (TS #4) Global climate change is affecting high latitudes the most. The average yearly temperature in the boreal zone between 64º and 90º of northern latitude has risen for 1.5ºC since the 1950s. Warming of the Arctic leads to excessive thawing of the permafrost and frozen ground that together account for 70% of the area. The petroleum industry is one of the main gross domestic product (GDP) drivers in the largest countries of the Arctic Communion, including the United States, Canada, and Norway. Petroleum engineering in the Arctic is challenging because the infrastructure needs to interact with the underlying permafrost. Permafrost-associated hazards—thaw-freeze heave, thermokarst lakes, and slope instability—lead to deformation and destruction of petroleum infrastructure, jeopardizing performance. Emergency accidents result in costly repair and potential human losses. Careful assessment of permafrost-related hazards is essential for geological and geotechnical investigation in the Arctic. This work focuses on evaluating the rate of permafrost degradation by studying geomorphologic features on the surface via remote sensing. The dynamics of these features are complicated (e.g., thermokarst lakes tend to increase in size due to thawing of surrounding permafrost and decrease when new drainage channels are formed within thawing ground). Time-series of remote sensing images are being assessed to detect changes in size and distribution of permafrost-related features east of Prudhoe Bay, Alaska, near Pumping Station 1 of the Trans-Alaska Pipeline System. The map of thermal anomalies will be produced using geo-informational systems (GIS) to discover the trends in temperature distribution in the area of interest. The goal of this research is to evaluate the rate of permafrost degradation in the area to help the management of petroleum engineering facilities in the High Arctic.

Use of Synthetic Aperture Radar for Detecting Subsidence Features in the Lower Mississippi River Valley Terracina, Steven, The University of Mississippi, ldyarbro@olemiss.edu; Lance D. Yarbrough, ldyarbro@olemiss.edu; Greg Easson, geasson@olemiss.edu; Bruce A. Davis, badavis3@olemiss.edu (Poster) The Mississippi River alluvial plain (MRAP) is a geophysical province in North America extending from the boot heel of southeast Missouri south along the Mississippi River to the Gulf of Mexico. This study focuses on the lower Mississippi valley portion of the Mississippi River alluvial plain (MRAP) geophysical province that extends from Memphis, Tennessee, to Vicksburg, Mississippi, and bordered by the Mississippi River to the west as well as parts of the MRAP of southern Louisiana.

Both areas are comprised of typically low strength alluvium, low relief, abundant surface water and shallow groundwater resources. The regions are susceptible to several geohazards including flooding, bank stability issues, regional and local subsidence, and expansive soils.

The New Madrid Seismic Zone to the north also poses additional risk 50

of seismic induced hazards (e.g. liquefaction). Characterizing potential subsidence is of great interest due to increased flood risk along lowlying areas near water bodies and impact on levee crest elevations. In this project, we investigated the use of interferometric synthetic aperture radar (InSAR) to detect subsidence. InSAR uses waveform phase information or similarly polarized radar pulses from two different acquisition dates with the potential to detect displacement on the order of a few millimeters. Our project utilized the SAR sensor onboard the European Space Agency’s Sentinel-1 platform. InSAR analysis relies on acquisition at two different times and for this project we selected acquisitions with fairly large temporal latency to capture possible displacement in our study area. Our results show regional subsidence rates are slower than the detectable limits using InSAR. Additional range (e.g. continued acquisitions) in the temporal database can lead to an improved method of subsidence detection and monitoring the study region.

The Reactor and the Volcano: A Risk-Informed Approach of the NRC to Assess Volcanic Hazards at New Nuclear Reactor Sites Thompson, Jenise, US Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Engineering and External Hazards, External Hazards Branch, Jenise.Thompson@nrc.gov; Gerry L. Stirewalt, gerry.stirewalt@nrc.gov; Brittain Hill, beames.hill@gmail.com; Laurel M. Bauer, Laurel.Bauer@nrc.gov (TS #4) Several nuclear power facilities previously licensed by the US Nuclear Regulatory Commission (NRC) considered volcanic hazards, as required by federal regulations for geologic site characterization. Of two reactors sited in the Pacific Northwest, one remains in operation with a design basis for a volcanic ash-fall event. For the review of those facilities, the NRC lacked clear guidance on an acceptable approach for assessing potential volcanic hazards in accordance with regulatory requirements. Future license applications might be considered for sites located in areas with potential volcanic hazards. In March 2020, the NRC issued draft guidance outlining an approach to assess volcanic hazards at proposed new reactor sites consistent with the risk-informed, performance-based regulatory framework of the NRC. The approach includes the following seven graded steps, all but one of which include off-ramps allowing early completion of the assessment based on risk insights: Step 1) Gather initial information for the time period and region of interest and develop a regional tectono-magmatic model, Step 2) Perform a deterministic screening of volcanic hazards from Quaternary volcanoes, Step 3) Develop initial risk insights, Step 4) Calculate eruption potential and/or hazard potential, Step 5) Develop detailed risk insights, Step 6) Evaluate the design bases of the proposed facility with respect to the volcanic hazards that might affect the site, and, Step 7) Evaluate actions for mitigating the hazards. If after all seven steps have been completed the volcanic hazards are beyond the design basis of the facility and cannot be effectively mitigated, the guidance recommends that an alternate site be considered. The guidance, once finalized, will give an applicant an acceptable approach for assessing volcanic hazards at a proposed site to ensure that any volcanic hazards present would not affect safe operation of the facility.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING Microbially Induced Desaturation (MID), a New Method to Mitigate Earthquake-Induced Liquefaction

The Hales Bar Project: Construction, Mitigation, and Removal of a Dam Founded on Karst

van Paassen, Leon, Arizona State University, leon.vanpaassen@asu.edu; Arash Khosravifar, karash@pdx.edu; Diane Moug, dmoug@pdx.edu; Edward Kavazanjian, Edward.Kavazanjian@asu.edu (TS #4)

Walker, Scott R., Tennessee Valley Authority, srwalker3@tva.gov (TS #5)

Earthquake-induced liquefaction is a major hazard that can damage critical infrastructure founded on loose sandy or silty soils. Cyclic loading of these soils during an earthquake may cause pore pressures to build up to a level at which the soil liquefies, causing slopes to fail and foundations to lose bearing capacity. Microbial Induced Desaturation (MID) is a new bio-based ground improvement method, which may be used to mitigate earthquake-induced liquefaction. MID relies on the injection of a nutrient solution typically containing calcium nitrate and calcium acetate that stimulates indigenous nitrate reducing bacteria to produce nitrogen gas, which desaturates the soil and increases the compressibility of the pore fluid, limiting pore pressure build up during cyclic loading and increasing the soil’s resistance to liquefaction. Field trials were performed in Portland, Oregon, at two sites underlain by liquefiable silty soils to evaluate the effectiveness of MID treatment. Monitoring results during these field trials indicated that MID was able to desaturate the soil at relatively large distance (at least 3.5 m) from the injection well and that desaturation was persistent for at least a year after treatment. If successful, this method may provide a cost-effective, sustainable method to mitigate earthquake-induced liquefaction under existing buildings.

Interactive Games for Teaching Site Investigation and Engineering Geology van Paassen, Leon A. Arizona State University, leon.vanpaassen@asu.edu; Dominique Ngan-Tillard, D.J.M.Ngan-Tillard@tudelft.nl; Peter N.W. Verhoef, P.N.W.Verhoef@tudelft.nl (Poster) In the 1970s and 1980s, Professor David Price developed a series of “games on site investigation and engineering geology” at Delft University of Technology (DUT) in The Netherlands, which have been in use ever since to teach undergraduate and graduate students concepts and strategies in Site Investigation and Engineering Geology.

Each game has a different application (bridge, harbor, airport, quarry, underground coal mining or tunnel) in a different engineering geological setting (alluvial, coastal, glacial soils and metamorphic, sedimentary rocks). In each game students receive a map, project instructions and some additional information about the geological setting. Based on this information, students have to recognize typical hazards related to their project and the geomorphological and environmental conditions. Next they have to go through different stages of site investigation and interpret the limited available information about the underground properties using structural geological interpolation techniques. Students can ask for additional information, but they have to decide on a strategy to order additional information, as time and budget are limited. Based on all information they have received they have to produce an engineering geological map and a report including their interpreted subsurface information taking into account potential uncertainties and provide answers and recommendations for the project design. Currently, these “games” are based on paper maps and handouts and requested subsurface information is handed out using interactive EXCEL databases. Efforts are being taken to upgrade these games so they can be used by students as online course materials and to allow for sharing these educational resources within the Engineering Geological Society.

September 2020

Located 33 river miles downstream of Chattanooga, the Hales Bar Project was the first multipurpose dam built on the main stem of the Tennessee River. Originally constructed by the Chattanooga and Tennessee Electric Power Company between 1905 and 1913, the site was chosen based on favorable topography with little regard to site geology. Built to both generate electricity and improve navigation through the Tennessee River Gorge, Hales Bar Dam was acquired by the Tennessee Valley Authority (TVA) in 1939. Almost immediately after construction, leakage was observed through the limestone bedrock foundation under the dam. Over time, underseepage increased to nearly 2,000 cubic ft per second with measured velocities greater than 4 ft per second. Mitigation attempts involved plugging seepage inlets in the bottom of the reservoir with a variety of materials (including surplus ladies corsets!), hot asphalt and cement grouting, and installation of a deep cutoff wall consisting of 18-in-diameter calyx holes backfilled with concrete. Despite millions of dollars in expenditures by both TVA and prior owners, leakage persisted. In 1963, TVA decided that Hales Bar Dam would be replaced, and Nickajack Dam (located 6 miles downstream) was completed in 1967. In addition to being founded on a different geologic foundation, the new dam also benefitted river traffic by allowing the undersized navigation lock at Hales Bar to be replaced with a larger structure. Following construction of Nickajack Dam, the spillway and nonoverflow sections of Hales Bar Dam were removed. A significant challenge with this operation was that in order to maintain navigation through the Gorge, the reservoir pool could not be lowered. In 1968, Hales Bar ultimately became the first federally owned dam to be removed because of geologic issues that an engineered solution could not economically address.

The Wheeler Dam Lock Failure: A Case History Walker, Scott R., Tennessee Valley Authority, srwalker3@tva.gov; Michael A. Morrison, mamorrison0@tva.gov (TS #5) Wheeler Dam, located in northern Alabama, is one of nine multipurpose projects on the Tennessee River. It was originally constructed between 1933 and 1936, and was the second dam completed by the Tennessee Valley Authority (TVA). The auxiliary navigation lock (60 ft wide by 360 ft long, 52-ft maximum lift) was designed by the US Army Corps of Engineers, and construction began in 1932 (pre-dating the creation of TVA). Construction of the larger main lock (110 feet wide, 600 feet long) began in October 1960 on the landside of the auxiliary lock. On the evening of June 2, 1961, a full tow heading upstream had just cleared the auxiliary lock. Unexpectedly, the lower miter gate land wall monolith began to slide into the excavation for the new main lock.

Shortly thereafter, neighboring wall monoliths began to slide, progressing upstream until a 436-ft-long segment of the auxiliary lock land wall had collapsed. Failure of the lock wall resulted in two fatalities and interrupted river traffic for over 10 months. TVA commissioned an independent investigation into the causes of the Wheeler disaster, and hired three independent consultants (two engineers and a geologist) to perform a complete investigation. This presentation will focus primarily on the underlying cause of the failure (which was determined to be geologic), with additional discussion of the innovative solutions to transport bulk commodities and oversize cargo around the dam (including one critical shipment that if delayed would have threatened the schedule for NASA’s Apollo Program) as well as the influence of this case history on the design and construction of other new navigation locks on the Tennessee River, including Pickwick Landing, Kentucky, and Chickamauga Dams.

AEG 2020 Virtual Annual Meeting – Program with Abstracts

51

AEG 2020 VIRTUAL ANNUAL MEETING Automated Rock Slope Monitoring: Lessons from the Colorado Rockies Weidner, Luke, Colorado School of Mines, weidner@mymail.mines.edu; Heather Schovanec; Brian Gray; Ryan Kromer; Gabriel Walton (TS #6) Remote monitoring of slopes is a rapidly emerging technique for quantitative hazard and risk management along geotechnical asset corridors. Some of the main outcomes might include identifying spatial failure patterns, rockfall volume return periods and erosion rates, climatic trigger patterns, and pre-failure forecasting, all of which inform the risk decision-making process. This talk describes work undertaken at the Colorado School of Mines, in collaboration with the Colorado Department of Transportation and independent consultants, incorporating the latest technological advancements into a fit-for-purpose rock slope monitoring workflow. Versions of the workflow have been implemented at several locations along highways passing through the Colorado Rocky Mountain region, which is regularly impacted by rockfall and landslide hazards. Sites are scanned at frequencies ranging from annually to daily using terrestrial lidar and SfM photogrammetry, then passed to an open-source processing workflow for alignment, change detection, and segmentation of individual failure events.

Machine learning can optionally be applied to adaptively filter and interpret raw data before calculation of displacement. In addition to describing the overall system architecture, this presentation will also cover challenges encountered and future research directions.

An Overview of Key Things to Consider When Designing a Construction Project Involving Naturally Occurring Asbestos (NOA) â&#x20AC;&#x201C; Setting the Stage For Success Zdeb, Thomas F., AECOM Technical Services, thomas.zdeb@aecom.com While the regulations, precautions, methods and procedures involved with asbestos found in building materials have been well established for decades, their applicability is challenged when Naturally Occurring Asbestos (NOA) is involved. An overview of some of the practical challenges encountered when attempting to design a successful construction project involving the disturbance of Naturally Occurring Asbestos (NOA) will be discussed. This will include determining regulatory requirements, developing sampling plans for surficial materials and those found at depth, deciding what types of asbestos and other potentially hazardous materials may need to be quantified, determining what detection limits may need to be applied, selecting a competent laboratory to perform the analyses, designating PPE and other requirements for workers based on potential exposures, collecting baseline air samples prior to the commencement of construction activities, deciding what detection limits for airborne asbestos may be needed and general considerations for personal, perimeter and community air monitoring programs.

LANDSLI IDE T E C H N O L O G Y A DIVISION OF CORNFORTH CONSULTANTS

10250 S.W. Greenburg Road, Suite S 111 Portland, Orego on 97223 Phone 503-4 452-1200 www.landslidetechno ology.com

La n d slides R oc kfa ll/R oc k S Slopes Geo t ec hn ical Asse t Ma n a ge emen t Emergen cy R es pon se In str umen ta tion SPRA T R ope A ccess T eam

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AEG 2020 Virtual Annual Meeting â&#x20AC;&#x201C; Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING

Author and Title Index Name

Title

Admassu, Yonathan

Lessons Learnt From the Use of Google Earth/Google Street View for Rockfall Hazard Rating

Albertson Jr., Leif E.

See Athey, Jennifer E.

Alexander, Gauen

Historic Analysis and Future Expansion of the Eisenhower-Johnson Memorial Tunnels, Part 2: Geotechnical Analysis

Alexander, Gauen

See Krajnovich, Ashton

Allstadt, Kate E.

See Mitchell, Andrew

Anderson, Douglas A.

See Stanczyk, Anna

Arthurs, James

Post-Eruption Transportation Repairs at Hawai’ian Volcanoes National Park

Athey, Jennifer E.

Alaska Radon Testing and Occurrence: Now That We Know Better, We Are Working to Do Better

Aydin, Orhun

See Sosa, Jacqueline

Bailey, Mark

An Overview of Analytical Test Methods for NOA

Balson, Tyler

See Mundell, John (2)

Balven, Matthew

Dam Failures in Hindsight. Lessons Learned?

Barker, Oliver

Towards a Model for the Permanent Eradication of Mine Related Asbestos Pollution in South Africa

Bateman, Vanessa

An Analysis of Fully Grouting Vibrating Wire Piezometers Use at Center Hill Dam (2012–2020)

Bauer, Jennifer

Landslide Features on the WNC Blue Ridge Escarpment - It’s a Complex Issue

Bauer, Laurel M.

See Thompson, Jenise

Beckman, E. Morley

Finding the American Tunnel: Using Directional Drilling Techniques to Intersect Abandoned Mine Workings

Blackwood, Timothy

Addressing Geologic Hazards in the Newell Creek Canyon Natural Area through Avoidance, Accommodation, and Mitigation

Bobyarchick, Andy R.

See Heavener, Emma

Booth, Adam

See Kingen, Kara

Boyer, Douglas

Current Status of Risk-Informed Decision Making for Dam and Levee Safety Programs

Braun, Greg

See Greene, Brian

Briggs, Stephanie M.

Unlined Spillway Erosion, Contributions from Hillside Channel Flow and Local Impinging Jet Scour at Oroville Dam, California

Brumbaugh, Ryan

See Mundell, John (1)

Burch, Scott

Assessment of 14 TVA Spillways and the Evaluation of Erodibility for Earth Cut Spillways

Burns, Scott

Radon-The Invisible Geological Killer—-Geologic Characteristics that Lead to High Radon Production

Burton, Rob

See Beckman, E. Morley

Capps, Denny M.

See Stanczyk, Anna

Castro, Pete

See Robinson, Rory (1)

Cato, Kerry

See Jordan, Frank

Cecka, Vladimir

See Burch, Scott

Chakrapani Lekha, Vishnu Improving Satellite-Based Precipitation Using Rain Gauge Observations for Landslide Prediction In A Data Sparse Region Chatterjee, Snehamoy

See Chakrapani Lekha, Vishnu

Chong, Jeng Hann

Estimating Sediment Discharge at a Sediment-Filled Dam in Malibu Creek Using Digital Elevation Models (DEM)

Colque, Percy

See Santi, Paul

Cook, Joseph P.

Landslide Mapping Along the I-17 Corridor, Central Arizona

Cording, Ed

Tunneling Group Keynote

Coupe, Brittany

The Influence of Deep-Seated Slope Failures on the Evolution of the Cretaceous Hogback Encircling the Black Hills, South Dakota

Cregger, David

Use of Wedge Analysis for Prediction of Rock Block Plucking Scour

Cronin, Vince

See Hobart, Catherine

September 2020

AEG 2020 Virtual Annual Meeting – Program with Abstracts

53

AEG 2020 VIRTUAL ANNUAL MEETING Name

Title

Cydzik, Kristina

See Shaller, Philip J.

Daanen, Ronald

See Hubbard, Trent

Dalal, Visty

“From Scoured to Safety” – Rehabilitation of Lake Roland Water Supply Dam, Baltimore, Maryland

Davidson, Kimberly

Effects of Anchoring on Uplift, Bluestone Dam, Hinton, West Virginia

Davis, Bruce A.

See Terracina, Steven

DeKoekkoek, Jill

See Robinson, Rory (1)

Deneuvillers, Christine

See Léocat, Erell

Devine, Tom

See Riley, Donald B.

Doroudian, Macan

See Shaller, Philip J.

Doughty, Megan

Mapping Increases in Hyporheic Exchange from Channel-Spanning Logjams

Dunbar, John

See Hobart, Catherine

Easson, Greg

Terracina, Steven

Eggers, Mark

See Hemraj, Dylan

Eisl, Holger M.

See Ilie, Ana Maria Carmen

Farmer, Samantha

Analysis of High Priority Unstable Rock Slopes in Great Smoky Mountains National Park, Tennessee and North Carolina

Farmer, Samantha

See O’Shea, Thomas

Fenster, David F.

See Stirewalt, Gerry L.

Ferry, Nicholas

Influence of Bedrock Substrate on Mobility of Large Rock Avalanches Formed in Dry Climates: Blue Diamond Landslide Case Study

Freitag, George

Pumice Mine Reclamation, Oregon State University – Cascades Campus, Bend, Oregon

Fuemmeler, Stephen

See Bauer, Jennifer

George, Michael F.

Back-Analysis of Unlined Rock Spillway Erosion Rates to Support Risk-Informed Design

George, Michael F.

See Briggs, Stephanie M.

Ghosh, Adit

See Chong, Jeng Hann

Godwin, William

See Riley, Donald B.

Gootee, Brian F.

See Cook, Joseph P.

Goss, Christoph

See Beckman, E. Morley

Gray, Brian

See Weidner, Luke

Greene, Brian

History of Internal Erosion at East Branch Dam, PA and Cutoff Wall Remediation Project

Gurrola, Larry D.

Flood History and Landslide Dam Hazards of the Montecito Watersheds, Santa Barbara County, California

Gutierrez, Marte

See Alexander, Gauen

Gutierrez, Marte

See Krajnovich, Ashton

Guy, Kerry

See Beckman, E. Morley

Harelson, Stephen

See Alexander, Gauen

Harris, Sarah

Residential Property Annual Slope Movement Monitoring in Erwin, Tennessee

Harris, Sarah

See Nandi, Arpita

Hauswirth, Scott

See Chong, Jeng Hann

Hayes, Kevin

Hydrogeologic Characterization of the C-23/24 North Reservoir Dam Site, Indian River Lagoon–South Watershed, Florida

Headland, Paul

King City Siphon –- Challenging Ground Conditions Drive Alignment Selection for a Vertical Curve Microtunnel

Heavener, Emma

GPR Investigation of Mine Subsidence Hazards in Charlotte, NC

Heckman, Ashley

See Headland, Paul

Hemraj, Dylan

Development of a Geotechnical Model for Open Pit Slope Design in Cenozoic Sediments in the Pilbara Region of Australia

Hess-Brittelle, Suzanne R. Phased Approach for Evaluating Piezometers to Inform a Risk Assessment, Blakely Mountain Dam, Ouachita River, Arkansas 54

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING Name

Title

Hill, Brittain

See Thompson, Jenise

Hirales-Rochin, Joel

Analysis of Geohydrological Risks based on SR & GIS from the Southeast Portion of the City of La Paz, Baja California Sur, Mexico

Hobart, Catherine

Dog Valley Fault as a Potential Threat to Stampede, Prosser Creek, and Boca Dams

Hubbard, Trent

Debris Flow Inventory and Hazard Assessment in Sitka, Alaska

Ilie, Ana Maria Carmen

Are Low-Cost Monitors Good Enough to Help People Understand Poor Air Quality in their Neighborhood?

Innes, David

New Technologies for Testing and Mitigating Radon in Air and Groundwater Residential Well Water plus a Radon 101 Review of Health Effects

Isaacson, J. Ike

Identification and Adverse Impacts of Carbonate Reef Structures for Tunnel Projects

Johnson, Erinn

See Beckman, E. Morley

Johnstone, Luke J.

See Mundell, John (2)

Jordan, Frank

Interrelationship of Faulting and Landsliding in the San Bernardino and San Jacinto-Santa Rosa Mountains

Kalika, Sarah

Asbestos Monitoring in Construction Site Air - Unexpected Challenges to Construction Site Monitoring

Katzenstein, Kurt

See Coupe, Brittany

Katzenstein, Kurt

See Reimers, Carson

Kavazanjian, Edward

See van Paassen, Leon (1)

Keaton, Jeffrey

When Can Four-to-Twelve Tests Be Sufficient for Engineering Design Parameters? A Tale of Two Papers

Kemeny, John

See Li, Echo

Khosravifar, Arash

See van Paassen, Leon (1)

Kingen, Kara

Climatic Controls on the Kinematics of the Hooskanaden Landslide, Curry County, Oregon

Kingston, William

See Burch, Scott

Kissick, Christopher

See Briggs, Stephanie M.

Korte, David

See Kroehler, Margaret

Krajnovich, Ashton

Historic Analysis and Future Expansion of the Eisenhower-Johnson Memorial Tunnels, Part 1: Geologic Modeling

Krajnovich, Ashton

See Alexander, Gauen

Kroehler, Margaret

Preliminary Investigation of Slope Movements in the North Cove Area, North Carolina

Kromer, Ryan

See Weidner, Luke

Kunkel, Forrest

See Mundell, John (1 and 2)

Latham, Rebecca

See Bauer, Jennifer

LeFebvre, Amy F.

See Hess-Brittelle, Suzanne R.

Léocat, Erell

Carto PMAi – a Project to Evaluate Worker and Public Populations Exposure to Elongate Mineral Particles of Interest

Leshchinsky, Ben

See Kingen, Kara

Li, Echo

A Machine Learning Algorithm for Rock Mass Characterization and Stability from Point Clouds

Liu, Kouqi

See Ogochukwu, Ozotta

Louie, John

Database of Geotechnical Shear-Wave Seismic-Velocity Profile Measurements for California and Nevada

Malone, Aaron

See Santi, Paul

Mann, Aras

See Bauer, Jennifer

Manning, Justin

Geologic Hazard Mapping of Mining Communities in Peru using Remote Sensing and GIS

Manning, Justin

See Santi, Paul

Marshall, Mike

See Freitag, George

Martin, Greg

See Freitag, George

Martin, James

See Riley, Donald B.

McDougall, Scott

See Mitchell, Andrew

McKinney, Robbi

Conceptual Site Model Strategy and Success Stories

September 2020

AEG 2020 Virtual Annual Meeting – Program with Abstracts

55

AEG 2020 VIRTUAL ANNUAL MEETING Name

Title

McMullen, Brian

See Robinson, Rory (1)

Medley, Edmund

Recent Advances in Stochastic Analyses of Slopes in Bimrocks and Bimsoils

Menounos, Brian

See Mitchell, Andrew

Meza, Pablo

See Santi, Paul

Millard, Tom

See Mitchell, Andrew

Mitchell, Andrew

Effect of Multi-stage Failures on Rock Avalanche Mobility: Joffre Peak Case Study

Morrison, Michael A.

See Walker, Scott R. (2)

Moug, Diane

See van Paassen, Leon (1)

Mundell, John

Geophysical Evaluation of Dam Seepage to Support Rehabilitation Efforts (1)

Mundell, John

Calibrating Artificial Intelligence and Hydrologic Modeling with Smart Monitoring Inputs for Enhanced Levee Safety Predictions Under Changing Climate Conditions (2)

Nandi, Arpita

Soil Creep and its Role in Mudslide Generation – Case Study from Erwin, Tennessee

Nandi, Arpita

See Farmer, Samantha

Nandi, Arpita

See Harris, Sarah

Nandi, Arpita

See O’Shea, Thomas

Nash, Art L.

See Athey, Jennifer E.

Ngan-Tillard, Dominique

See van Paassen, Leon A. (2)

Nichols, Holly J.

See Briggs, Stephanie M.

Noyes, John

How Training and Education in Radon Mitigation has Provided Invaluable Insights for Vapor Mitigation: Supported by Three Case Studies

Ogochukwu, Ozotta

Change of Bakken Shale Stiffness due to CO2 Saturation

Oommen, Thomas

See Chakrapani Lekha, Vishnu

Oommen, Thomas

See Tcibulnikova, Iuliia

Ortega, Jacob

See Louie, John

O’Shea, Thomas

Investigating Risks Related to Unstable Slopes in Great Smoky Mountains National Park

O’Shea, Thomas

See Farmer, Samantha

Ostadhassan, Mehdi

See Ogochukwu, Ozotta

Piepenburg, Michael

Behavior of the Chagrin Shale in Selected Tunneled Excavations, Cleveland, Ohio

Pope, Isaac

Reaching New Heights: The Cascade Volcanoes as Exemplary Laboratories for Applied Geoscience

Pope, Isaac

Poorly Sorted Terrace Deposits of the Cispus Valley: Glacial Drift or Mount Adams Lahar?

Powell, Jack

See Blackwood, Timothy

Prince, Phil

See Bauer, Jennifer

Pringle, Patrick T.

Tree-Ring Analysis (Dendrochronology), a Tool for Dating of Subfossil Forests – Victim Tree Examples from Mount Rainier lahars and the Bonneville Landslide

Reimers, Carson

Use of Close-range Photogrammetry to Generate 3D Models of Drill Core

Richard, Patrick

See Léocat, Erell

Riley, Donald B.

Rock Quality Characterization Using Blast Hole Penetration Rate Data USACE Isabella Lake Dam Safety Modification Project Kern County, California

Robinson, Larry

See Robinson, Rory (2)

Robinson, Rory

Prevention and Recording of a Large Landslide Event Using Ground-Based Interferometric Radar at Roberts Mountain, Oregon (1)

Robinson, Rory

US Highway 20, Between Pioneer Mountain and Eddyville, Oregon: The Observational Design Approach, Now Post-Construction (2)

Rogers, Bryce

See Robinson, Rory (1)

Rogers, J. David

Site Characterization of Levee Foundations

Rogers, J. David

See Gurrola, Larry D.

56

AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

AEG 2020 VIRTUAL ANNUAL MEETING Name

Title

Roggenthen, William

See Reimers, Carson

Sajinkumar K S

See Chakrapani Lekha, Vishnu

Santi, Paul

Environmental and Geologic Hazards near Small-Scale Gold Mines in Peru: An Analog for 19th and Early 20th Century Mining in Colorado

Sawyer, Audrey

See Doughty, Megan

Schovanec, Heather

See Weidner, Luke

Schweiger, Paul

See Burch, Scott

Shakoor, Abdul

See Keaton, Jeffrey

Shakoor, Abdul

See Kroehler, Margaret

Shaller, Philip J.

Construction, Operation, and Failure of Ka Loko Dam, Kauai, Hawaii

Sharp, Josh

See Santi, Paul

Shrestha, Parmeshwar L. See Shaller, Philip J. Simpson, Alexander R.

See Louie, John

Singha, Kamini

See Doughty, Megan

Smith, Nicole

See Santi, Paul

Smith, Sarah

See Briggs, Stephanie M.

Smoot, Emily

An Investigation and Comparison of Stable Isotopes in Meteoric Waters and Groundwaters from Southern Washington

Sosa, Jacqueline

Preparing for The Big One: Data-Driven Spatio-Temporal Risk Maps for Earthquake Evacuation in L.A. County

Stanczyk, Anna

Permafrost Thaw, Precipitation, and the Pretty Rocks Slump - A Climate Change Induced Landslide in Denali National Park?

Stirewalt, Gerry L.

Introduction to the Session on Applied Geoscience Methods for Problem Solving

Stirewalt, Gerry L.

See Thompson, Jenise

Sturmer, Daniel

See Ferry, Nicholas

Szabo, Zoltan

Radon-222 Occurrence in Groundwater is Highest in Appalachian Piedmont, Eastern USA and Correlates to Lead-210 Occurrence

Tardif, Michael

See Robinson, Rory (1 and 2)

Tcibulnikova, Iuliia

Permafrost Degradation as Geological Engineering Challenge in Alaska: Application of Remote Sensing Techniques

Terracina, Steven

Use of Synthetic Aperture Radar for Detecting Subsidence Features in the Lower Mississippi River Valley

Terres, Don

See Riley, Donald B.

Thompson, Jenise

The Reactor and the Volcano: A Risk-Informed Approach of the NRC to Assess Volcanic Hazards at New Nuclear Reactor Sites

Tollefson, William

See Nandi, Arpita

Utevsky, Nora

See Freitag, George

van Paassen, Leon

Microbially Induced Desaturation (MID), a New Method to Mitigate Earthquake-Induced Liquefaction (1)

van Paassen, Leon

Interactive Games for Teaching Site Investigation and Engineering Geology

Verhoef, Peter N.W.

See van Paassen, Leon A. (2)

Walker, Scott

The Hales Bar Project: Construction, Mitigation, and Removal of a Dam Founded on Karst (1)

Walker, Scott

The Wheeler Dam Lock Failure: A Case History (2)

Walker, Scott

See Burch, Scott

Walton, Gabriel

See Weidner, Luke

Ward, Hans Abramson

See Briggs, Stephanie M.

Weidner, Luke

Automated Rock Slope Monitoring: Lessons from the Colorado Rockies

White, Joseph

See Hobart, Catherine

Whitelaw, Michael

See Harris, Sarah

Whitelaw, Michael

See Nandi, Arpita

Wilhite, Coralie

See George, Michael F.

September 2020

AEG 2020 Virtual Annual Meeting â&#x20AC;&#x201C; Program with Abstracts

57

AEG 2020 VIRTUAL ANNUAL MEETING Name

Title

Wohl, Ellen

See Doughty, Megan

Wojtanik, Rod

See Blackwood, Timothy

Wooten, Richard

See Kroehler, Margaret

Wurst, Philip

See Robinson, Rory (1)

Yarbrough, Lance D.

See Terracina, Steven

York, DeShana D.

See Athey, Jennifer E.

Zdeb, Thomas

An Overview of Key Things to Consider When Designing a Construction Project Involving Naturally Occurring Asbestos (NOA) – Setting the Stage For Success

Zhou, Wendy

See Krajnovich, Ashton

Zhou, Wendy

See Manning, Justin

Zhou, Wendy

See Santi, Paul

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AEG 2020 Virtual Annual Meeting – Program with Abstracts

September 2020

e h t e v Sa ate…for These Future AEG Events D AEG 2021 Annual Meeting Westin Riverwalk – San Antonio, Texas

September 18–26, 2021

spots around. Perhaps most notable of all San Antonio’s missions is the Alamo in the heart of downtown. The Westin Riverwalk, located on the Riverwalk’s quiet end, is a beautiful upscale hotel decorated to emphasize the historic Texas surroundings while providing a warm and subtle Spanish Colonial look and feel. Don’t miss this opportunity to be adventurous and inspired in this amazing city rich in history and culture!

AEG 2023 Annual Meeting

Portland Marriott Downtown Waterfront – Portland, Oregon September 19–24, 2023

AEG 2022 Annual Meeting Planet Hollywood Resort – Las Vegas, Nevada September 13–17, 2022

Once a frontier settlement in the Wild West, San Antonio’s unique culture stemming from its Spanish, German, and American roots offers an abundance of history, arts, and exciting cuisine. The city is famous for its scenic River Walk, which makes getting around downtown a breeze.

Stretching more than 24 kilometers from start to finish, the River Walk’s shaded pathways connect hundreds of shops, restaurants, hotels, historic landmarks, museums, and attractions. Take the River Walk to the north and you’ll find museums—filled with everything from Picassos to Western memorabilia—and the Pearl—an exciting culinary and shopping destination. To the south, the River Walk leads to four Spanish missions that once provided shelter for frontier settlers and still provide some of the best bird watching

Your fun begins on The Strip, Las Vegas’ main artery and home to bustling casinos, world-class restaurants, ornately designed resorts and over-the-top shows. Overlooking the Las Vegas Strip, our Annual Meeting hotel—Planet Hollywood Resort—is in the middle of everything you will want to experience. This Annual Meeting will be exciting, educational, and a great opportunity to reconnect with your colleagues and meet new ones.

The In-Person AEG 2020 Annual Meeting has been rescheduled for 2023.

Portland, Oregon’s largest city, sits on the Columbia and Willamette rivers, in the shadow of snow-capped Mount Hood. It’s known for its parks, bridges, and bicycle paths, as well as for its eco-friendliness and its microbreweries and coffeehouses. The city hosts thriving art, theater, and music scenes. Surrounded by Portland hot spots, the Marriott Portland Downtown Waterfront hotel reflects the vibrancy of the city and is located directly on the waterfront in downtown, surrounded by more than 60 breweries. Wind down with friends by sampling some of the 150 types of whiskey at their on-site restaurant, Proof Reader. The hotel even helps you go green with complimentary car-charging stations, biodegradable straws and easy access to light rail from the nearby Morrison Subway Station.

At night, retire to elevated guest rooms with 24-hour room service, waterfall showers, free Wi-Fi, premium channels and views of Portland. Don’t miss all of the exciting Field Courses, Guest Tours and the Special Event at the Oswago Hills Vineyard planned for this incredible Annual Meeting.

AEG Sea-Level Rise Conference – Norfolk, VA May 5–7, 2021

While the media are focused on the COVID-19 pandemic, many scientists and engineers continue to follow research on other long-term issues, both nationally and internationally. AEG members are aware of changes that are coming as a result of climate change and the subsequent rise in sea level, which will have worldwide effects. Many researchers expect the eastern coastline of the United States will be affected dramatically. Because climate change and rising sea levels are of interest to professionals in a wide variety of disciplines, we expect to involve other organizations in the planning and execution of this conference. We have received interest from the US Army Corps of Engineers, the American Planning Association, and the American Meteorological Society.

Do you have ideas for talks you would like to see, or would you like to help plan this meeting? We welcome your input. Please send your suggestions/thoughts to Rick Kolb, Southeast Regional Director, (rick.kolb1@gmail.com), Ryan Fandray, Mid-Atlantic Regional Director, (r.fandray@gaiconsultants.com), and Curt Schmidt Northeast Regional Director, (schmidtcas.aeg@gmail.com).

Advance your career with a masterâ&#x20AC;&#x2122;s degree in applied geosciences at Penn Whether youâ&#x20AC;&#x2122;re an experienced geoscientist or are preparing WR HQWHU WKH È´HOG 3HQQÈ&#x2021;V ULJRURXV 0DVWHU RI 6FLHQFH LQ $SSOLHG *HRVFLHQFHV 06$* LV D KLJKO\ SUDFWLFDO SURJUDP WKDW KHOSV \RX take your next step. With a faculty of leading experts and courses designed to accelerate professional licensure, we know what you need to move forward in your career.

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