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Supervolcanoes and calderas !. The Volcanic Explosivity Index- how big is a supereruption ?. VEI- 5 Plinian, Mt St Helens. VEI 3 Vulcanian Montserrat. VEI 1 Hawaiian. VEI 6 Ultra-plinian Mt Pinnatubo. VEI 8 Imagine 100 Pinnatubos erupting at the same time.
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The Volcanic Explosivity Index- how big is a supereruption ? VEI- 5 Plinian, Mt St Helens VEI 3 Vulcanian Montserrat VEI 1 Hawaiian
Caldera - created from large, explosive eruptions of felsic pyroclastic material. The caldera is created when the roof of the magma chamber collapses. Can be 10’s km’s across Different from a crater E.g., Yellowstone, WY, 1 m.y. Supervolcanoes and calderas !
Supervolcano ! http://youtube.com/watch?v=Abg5-gLdEb0
Why are supervolcano eruptions so big ? • A) There is a higher % of gas in the magma • B) The collapsing magma chamber roof helps the eruption • C) The magma is more viscous • D) A large volume of magma was ready to erupt • E) Eruptions occur simultaneously from a ring of vents. http://www.cotf.edu/ete/movies/caldera.mov
Which type of volcano would you rather live beside and why? Cinder cone Stratocolcano(composite) Sheild volcano Supervolcano with caldera