GEOLOGY 105 Final: Volcanic Hazards
29 Dec 2016
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Document Summary
Ash fall: very slippery, acts like mud, sticks to any surface. Move more quickly and can surmount topography such as hills and ridges. Their effects are more widespread and less predictable. Three types: soufriere type- the eruption column can no longer be sustained (due to loss of pressure), so the column collapses forming pyroclastic flows on the flans of the volcano. They tend to be cooler than the others: pelee type- a dome of viscous magma is blocking the conduit. Eventually it explodes under pressure, blasting pyroclastic material down one of the flanks of the volcano. If it is extremely violent it could produce a lateral blast: merapi type- a dome of viscous magma grows in the grater. Eventually it gets so large, it collapses under gravity, producing a pyroclastic flow. Mud flows: el chichon- over 2,000 people were killed by a succession of three pyroclastic surges.
