What Is The Life Cycle Of A Volcano?

What Is The Life Cycle Of A Volcano?

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Build Up Of The Earth / Tectonic plates

Tectonic Hotspot

Convergent Plates subductive

Divergent Plates constructive

As the pressure from the rising magma increases, it eventually punches through the crust, rapidly expanding due to gases that are trapped being released.

As the lava cools on the earths surface and solidifies, a cone begins to form often built up in layers from serveral eruptions.

Pyroclastic ow - this is the most dangerous and fast moving feature of a volcanic eruption (travelling upto 700km/h and reaching temperatures of up to 1000 C).

It contains hot ash and rocks flung from the top of the volcano as it erupts.

How A Volcano Is Formed / Eruptions

The ash cloud caused by a volcanic eruption can also cause problems such as clogging aeroplane engines or even affect the weather

Above the ground, magma is classified as lava

Shield Volcano

Made up of solidified lava creating a large but shallow shape

Cinder Volcano

Made up of ash and burnt rock creating a small cone

Composite Volcano

Made up of alternating layers of ash and solidified lava creating a steep and moderately large cone

Different Tyes Of Volcanoes

80% of volcanoes form under the ocean

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Shocks from Krakatoa’s 1983 eruption (Indonesia) were felt in Australia and California

A shock wave was sent round the globe seven times

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Effects Of An Eruption

Usain Bolt after two seconds at top speed

Mount Nyiragongo (1977) after two seconds at top speed

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Poisonous gas released from Nyos (Cameroon) in 1986

52 livestock killed

52 people killed

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When there is no volcanic activity occuring, a volcano is considered dormant.

percentage of the globe’s surface covered in volcanic soil

Dormant Volcanoes

The soil surrounding is particulary fertile due to the products of past eruptions; therefore it is of particular agricultural interest

percentage of the world population fed by food grown on volcanic soil

Collapsing Cones

In some volcanoes an imense amount of pressure can build up, perhaps due to a long period without an eruption

Once enough pressure has built up, a massive eruption will occur which can cause the top of the volcano to collapse

After the 1980 eruptions of Mt St Helens, its height was reduced by 390m leaving a crater 2 miles in diameter.

Collapsing Cones / Secondary Vents Secondary Vents

Cracks can occur on the inside of the volcano, meaning that sceondary vents begin to form

Once enough pressure has built up, lava will spew forth from the weakened point in the volcano

After lava has erupted from the secondary vent, lava solidifies and a parasitic crater begins to form

A volcano is considered extinct when it has not erupted for thousands of years. However, some particularly large volcanoes, known as supervolcanoes, can not erupt for ten thousand years and still become active again. When they do erupt it is a massive explosion.

One way that volcanoes can go extinct is when movement of tectonic plates moves the volcano away from a hotspot, cutting it off from its supply of magma, causing it to cool

Extinction / Super Volcanoes

Regular volcanoes erupt far more frequently than supervolcanoes. Each smaller dot is an eruption from Mt Vesuvius in the past 10,000 years compared to the one eruption from Yellowstone Caldera