GEOL 1121 Lecture 2: Geology Test 2
Document Summary
St. helen is an example of volcano collapse triggering pyroclastic flow: convergent margin volcanoes, key hazards include, lahars or mudflows that come down the river valleys, pyroclastic flows, ash falls and clouds, landslides, climate cooling for large eruptions. Lahars: mud/ash flows primarily down river valleys, can be very hot, extremely dangerous. Rainier may contribute to lahars during and eruption because the ice will melt and turn to water. Pyroclastic flow and cloud hazards: essentially mixes of gas and ash, denser than air so they sweep down the sides of mountains at an excess of 100 mph, this of shaking a coke and then opening it. The soda comes out very quickly: lavas rich in sio2 and is very viscous, can be wide spread with big blast zone. Monitoring volcanoes: the italian peninsula is a convergent (subduction) margin causing volcanoes. Review: volcanic hazards, primarily related to gas-rich, viscous magmas of convergent margin volcanoes, key parameter: volume of pyroclastic material, mt.
