EARTHSC 2GG3 Chapter Notes - Chapter 4: Mount St. Helens, Subduction, Magma Chamber
1 Oct 2016
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Document Summary
Chile tsunami: chile was the largest eq ever recorded, caused tsunamis. 3 waves killed more than 2000 people, then follow up waves killed more. Largest tsunamis that would affect people would be from subduction zone eqs (ex. Kilauea volcano, hawaii - slumping towards the sea, volcanic flanks. Canary islands: catastrophe in waiting for coastal cities, evidence of repeated collapse of volcanic flanks: volcanoes. Volcano: cone shaped hill/mountain formed when molten rock/gases reached the earth"s surface and erupt. Lava: magma after it reaches the earth"s surface. Melting temperature depends on pressure and availability of water. Magma rises through crust because it is less dense than surrounding rock, breaks off and can incorporate surrounding rocks. Eruption depends on magma viscosity, quality of water vapour/volatile gases, type and amount of magma. Viscosity: how fluid magma is (high = thick and pasty), due to differences in amount of silica (tetrahedral structure) Basalt: black or dark, fine grained volcanic rock.
