Lec 12 W 9 Tues Volcanic activity hazards

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Unformatted text preview: ell, then will deflate as magma moves ____ into the pipe to be expelled at the summit. Forecasting Methods - detectors to measure sulfer dioxide Geochemical indicators • changes in gas rate emissions and ___________ chemistry SO2 from the vent Gas monitoring station 12 Forecasting Methods Remote sensing Thermal changes increase in surface temperature Magnetic changes magnetic change the original ________ properties of the cold rock - may be influenced by magnitype crystals in the magma Changes in hydrologic conditions increased melting of snow fields Processes Volcanoes: natural systems, processes Risk Assessment: related to perception Hawaii increased awareness of risk limited U.S. Pacific Northwest: ______ risk awareness, based on education - populations - have to respect the hazard Hazards??? Population related, many people live in the shadow of large volcanoes Why? No choice, history … Perception of the hazard??? Hazard Evaluation and Preparedness - make dams Methods to Control Lava Flows: - douce with water (flow that way) 1. Diversion: creating blockages _________ in a confined area and diverting flow - use of bombs to make holes, divert flows a)Use of earth dams (if a nonpopulated area is available to divert lava flow into b)Bombing (to produce craters or to enlarge preexisting features to serve as catchment areas) 13 Hazard Evaluation and Preparedness Methods to Control Lava Flows chilling 2. Hydraulic _______ (e.g., as used in Iceland) To be useful, flows must be slow moving Requires access to lots of water Hazard Evaluation and Preparedness - figure out plans if event actually happened Long Valley Eruption 700,000 yrs ago Potential hazard Hazard from flowage events R. 120 Km Ash 1m Hazard Evaluation and Preparedness Hazard Debris Flows: Proximity of population to natural volcanic process Population along river _______ (natural valley conduits for flows) 14 Hazard Evaluation and Preparedness Risk evaluation • Ongoing monitoring Preparedness through • Education • Event contingencyplans _________ - what do IF it happens End of Lecture 15...
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This document was uploaded on 02/25/2014.

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