ERTH 2415 Lecture Notes - Lecture 16: Santorini Caldera, Types Of Volcanic Eruptions, Magma Chamber
3 Dec 2015
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Document Summary
Tectonic environments: mostly subduction zones, hot spot: magma composition: andesitic to rhyolitic, high viscosity, high volatile content, very large volume, largest explosive volcanic eruptions, two different phenomena: Collapse of existing stratovolcano into partially emptied magma chamber: follows a plinian-type eruption that opened void space below the volcano, piston-like action of collapsing volcano cause very large volume of magma to flow outward as pumicerich sheets. Explosion blows the existing volcano apart completely: examples: krakatoa, santorini, caldera when volcano collapses, circular feature left behind is the caldera. Crater lake, oregon: calderas and central vents. Similarities: both are circular features associated with volcanoes. Differences: central vents are created by explosions. Calderas are collapse features: 1883 krakatoa, indonesia volcanic eruption and tsunami. Subduction of australian plate under eurasian plate along west coast of indonesia. Size of explosion 100 megatons (20 kilotons at hiroshima) Explosion heard on 1/3 of earth"s surface. More importantly: ocean-bottom telegraph cables transmitted the news around the world.
