Seismic scenario and earthquake timeline Data* from the Pacific Northwest Seismic Network (PNSN) indicate a 43 percent to 63 percent chance of a 8.0 to 9+ magnitude Cascadia event in the next 50 years. The probability of an event on the South Whidbey Island fault, Seattle fault or the Lake Creek Boundary fault adds to the chance of a seismic event in Clallam and Jefferson counties. There have been 19 quakes of 9+ and 22 quakes of 8+ over last 10,000 years, averaging every 200 years. The chances of earthquakes increase as other faults are considered, particularly Lake Creek Boundary. Combining the risk of either Lake Creek Boundary Fault or a CSZ event raises Clallam County risk to higher than 50 percent in the next 50 years.
Cascadia Subduction Zone Seismic Scenario Shaking Intensity for Washington
Source: Department of Natural Resources
*Provided by John Vitale, director of the Southern California Earthquake Center, former director PNSN
high
low
Clallam
active fault
Jefferson
scenario fault
0
50
100
miles
Source: USGS
Peninsula Daily News/Sequim Gazette
PENINSULA EMERGENCY PREPAREDNESS GUIDE
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FEBRUARY 2018
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