Teacher resources and professional development across the curriculum

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Subduction Zone Volcanoes

Run Time: 00:05:24

Scientist Britt Argow and geoscientist Chuck Blay, of Teok Investigations, describe that, due to the differing thickness and density of continental and oceanic crusts, basaltic ocean crust is subducted under less-dense granitic continental crust. This happens at plate margins where these two types of crust collide. Britt Argow and teacher Joe Reilly discuss how, at subduction zones, ocean crust is forced down to a zone of higher pressure. Volcanologist Dave Sherrod, of the Hawaii Volcano Observatory, USGS, and geologist Keith Klepeis, of the University of Vermont, describe the oceanic crust. Oceanic crust carries a load of CO2-rich sediment and water, which changes the chemistry of the crust, allowing the rock to melt and to form magma (molten rock) at a lower temperature than would usually be required. Magma from this type of rock is enriched with highly-pressurized steam and CO2 and rises to the surface and forms volcanoes. This kind of volcano usually erupts explosively. A good example is Mount St. Helens, which exploded on May 18, 1980, killing 57 people. Featured Scientists: Chuck Blay, Ph.D., Keith Klepeis, Ph.D., Andy Kurtz, Ph.D., Michael Manga, Ph.D., and David Sherrod, Ph.D.


NSES Standard

High School Standard D. Earth and Space science


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