ATOC 185 Lecture Notes - Lecture 1: Viscoelasticity, Andesite, Volcanism
8 Jan 2019
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Document Summary
Molten magma rises w/in the earth and is erupted either quietly (lavas) or violently. Some volcanoes have both quiet and violent activity (difficult to decide is it can go from lava to explosive volcano. Ex: may 1980 violent eruption in the us after a month lava started coming out. Happens infrequently we have never seen one in our days. Ex: yellowstone was a supervolcano thousands of years ago. Magmas w/ higher silica (sio2) contents are more vicious. Gas in magma sticky, vicious ( Slow movement : stretches out doesn"t fragment (non-explosive) Fast movement : breaks apart fragments (explosive) because of all the gas that. Magma : molten rock stored in the earth"s crust makes it move fast. Ex: lengai a lot of gas (= fast flows), changes form with atmosphere and color with time, and glows at night. Volcanoes are located on plate boundaries (plates diverge) Ex: a plate boundary goes through iceland= many volcanoes in the area.
