HR: 10:50h
AN: V32A-03    [Abstracts]
TI: Assessing Volcanic Threat and Prioritizing Volcano Monitoring in the United States
AU: * Ewert, J W
EM: jwewert@usgs.gov
AF: U.S. Geological Survey, Cascades Volcano Observatory, 1300 SE Cardinal Ct., Vancouver, WA 98683 United States
AU: Guffanti, M
V32A-03 AF: U.S. Geological Survey, 12201 Sunrise Valley Dr., Reston, VA 20192
AU: Murray, T L
V32A-03 AF: U.S. Geological Survey, Alaska Science Center, 4200 University Dr., Anchorage, AK 99508 United States
AB: A methodology to characterize and rank volcanic threat was developed to prioritize monitoring improvements on a national scale. 169 Holocene-age U.S. volcanoes are ranked by level of threat based on scoring of various hazard factors (for example, explosivity, frequency of eruptions) and exposure factors (for example, nearby population and infrastructure, aviation) that were chosen to give a balanced view of unmitigated volcanic threat. For each volcano, the sum of its hazard score times the sum of its exposure score gives a numerical threat score. The distribution of scores for all 169 volcanoes defines five threat groups ranging from Very High to Very Low. Higher-threat volcanoes warrant better early-warning monitoring capability than lower-threat volcanoes. Accordingly, the adequacy of the current monitoring level at each volcano is rated on our ability to characterize ongoing and expected activity based on the types, numbers, and location of monitoring instrumentation now in place at each. The current monitoring level is compared to the level warranted by a volcano's threat score to determine if it has a significant "monitoring gap". The gap analysis systematically identifies hazardous volcanoes where monitoring is inadequate for the threats posed such as in the Cascade Range. This analysis also highlights serious monitoring inadequacies in Alaska and the Northern Marianas where the volcanic-ash hazard to aviation is high yet numerous volcanoes have no monitoring whatsoever; from a hazards perspective these regions can no longer be considered remote. The results of the U.S. volcanic threat assessment are being used to guide long-term improvements to the national volcano-monitoring infrastructure operated by the USGS and affiliated partners and to establish a National Volcano Early Warning System. Given the time required to install instrumentation and telemetry in volcanic areas and the need to provide reliable scientific interpretation of the progression of unrest, improvements need to be implemented well in advance the onset of unrest.
DE: 8488 Volcanic hazards and risks
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005