ERTH 2415 Lecture Notes - Lecture 11: Tseax Cone, Pyroclastic Flow, Magma Chamber
26 Apr 2016
School
Department
Course
Professor
Document Summary
Tectonic environments mostly subduction zones hot spot: magma composition andesitic to rhyolitic. Largest explosive volcanic eruptions: two different phenomena 1. Cataclysmic explosion: volcano collapse: 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 pumice- rich sheets. Both are circular features associated with volcanoes: differences. Calderas are collapse features: cataclysmic explosions: explosion blows the existing volcano apart completely. Krakatoa, indonesia: final cataclysmic explosion completely destroyed volcano: walls of volcano ruptured, ocean water invaded magma chamber and flashed into vapor, steam explosion. Hot enough to cause burn-related fatalities 40 km away. Reached 2,500 km downwind after several days. Shielded sunlight: global temperatures dropping by 1. 2(cid:0) c the following year. Similarities with krakatoa helped understand the sequence of events: cataclysmic explosion. In santorini, 4-10 times more pyroclastic material was ejected: tsunami.
