SLE102 Lecture Notes - Lecture 9: Land Degradation, Pumice, Volcanism

• School: Deakin University
• Department: Science, Engineering and Built Environment
• Course: SLE102
• Professor: Nick Porch

Document Summary

Volcanic eruptions, earthquakes, tsunamis, landslides, geomagnetic storms, sand dune migration. Disaster: only occurs when a hazard intersects with human activity (people, property, possessions) Risk: (cid:862)the (cid:272)ha(cid:374)(cid:272)e of loss to the su(cid:271)je(cid:272)t (cid:373)atter of a(cid:374) i(cid:374)sura(cid:374)(cid:272)e (cid:272)o(cid:374)tra(cid:272)t(cid:863); the (cid:272)ha(cid:374)(cid:272)e of financial loss. Risk = hazard in relation to people + property. Explosive eruptions: high silica magma; viscous magma; lots of gas, occur at subduction zones of converging plates, pyroclastic flows, lahars/mud flows, pyroclastic (ash) fall. Pyroclastic flows: mix of superheated gas and volcanic particles which flow down slopes with coarse particles suspended in gas/fine particle mix. Two parts: basal flow of mainly coarse particles + turbulent cloud of gas and fine particles. Very fast (travel up to 700km/hr) and hot. Volcanic activity melts snow and ice on slopes melted snow runs down side of volcano water picks up rocks and debris for(cid:373)s fast flowi(cid:374)g, high e(cid:374)ergy (cid:858)(cid:373)ud a(cid:374)d de(cid:271)ris flows(cid:859).