HR: 0800h
AN: V21C-0615    [Abstracts]
TI: Seismic, Webcam and Satellite Observations of Eruptions at Veniaminof Volcano, Alaska, January-February 2005
AU: * DeRoin, N
EM: fsnd3@uaf.edu
AF: Geophysical Institute, University of Alaska Fairbanks P.O. Box 757320 903 Koyukuk Dr., Fairbanks, AK 99775 United States
AU: McNutt, S R
EM: steve@giseis.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks P.O. Box 757320 903 Koyukuk Dr., Fairbanks, AK 99775 United States
AU: Williams, E
EM: earlew@ll.mit.edu
AF: MIT, Parsons Laboratory 15 Vassar St., Cambridge, MA 02139 United States
AB: Previous studies of 21 to 50 volcanic eruptions around the world [McNutt, 1994; 2005], showed a linear correlation between maximum tremor reduced displacement (DR) and Volcanic Explosivity Index (VEI) during the eruptions. However, these studies only compared the maximum DR of the entire eruption with the maximum plume heights or VEI, using one data pair per eruption. Here we examine a case study of the eruption of Mt. Veniaminof, Alaska, which occurred from January 2 to February 21, 2005. This eruption produced many ash plumes as well as nearly continuous seismic activity, so it is possible to determine relations between seismic and eruptive activity for hundreds of small events. We compared ash plume heights from Veniaminof to magnitudes of low-frequency (LF) earthquakes that preceded the plumes. Seismic data are provided by an array of 8 short-period (T=1s) seismometers around Veniaminof. A webcam in Perryville, Alaska, 35 km away, recorded images of Veniaminof every five minutes during the entire eruption. Plume heights were measured from the webcam images, although poor weather resulted in a limited number of days in which the plumes were visible, and windy conditions made measurements of some plume heights difficult. Nevertheless we found that plume heights are proportional to magnitudes of LF earthquakes, albeit with significant scatter. Plume heights varied from 0.06 to 1.75 km and earthquake magnitudes from 0.6 to 1.6, corresponding to DR of 0.7-8.8 cm2. A preliminary search showed that eight eruptions were recorded on DoD satellite data, with signal-to-noise ratios of up to 1 order of magnitude. The larger radiance values corresponded to the larger seismic events. Thus the high resolution results for Veniaminof generally confirm the more general results of earlier studies, and also provide improved data to study distributions and variance.
DE: 7280 Volcano seismology (8419)
DE: 8419 Volcano monitoring (7280)
DE: 8488 Volcanic hazards and risks
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005