HR: 1340h
AN: V33C-1475    [Abstracts]
TI: Lava Flow Mapping at Westdahl Volcano, Alaska, Using SAR and Optical Satellite Imagery
AU: * Rykhus, R
EM: rykhus@usgs.gov
AF: U.S. Geological Survey, EROS Data Center, SAIC, 47914 252nd Street, Sioux Falls, SD 57198 United States
AU: Lu, Z
EM: lu@usgs.gov
AF: U.S. Geological Survey, EROS Data Center, SAIC, 47914 252nd Street, Sioux Falls, SD 57198 United States
AU: Masterlark, T
EM: masterlark@usgs.gov
AF: U.S. Geological Survey, EROS Data Center, SAIC, 47914 252nd Street, Sioux Falls, SD 57198 United States
AU: Dean, K G
EM: ken.dean@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, P.O. Box 757320, Fairbanks, AK 99775 United States
AB: Field mapping of young lava flows at Aleutian volcanoes is logistically difficult. Optical imaging systems, whether air- or space-borne, can be valuable to such mapping efforts, but are often inhibited by persistent cloud cover in this area. These factors have resulted in erroneous estimates of the area and volume calculations of three young lava flows at Westdahl volcano, including its most recent flow (1991-1992). We combined synthetic aperture radar (SAR) data with multispectral Landsat-7 ETM+ imagery to distinguish among the 1991-1992 flow, the 1964 flow, and a pre-1964 flow, and to calculate the flow areas (8.4 km2, 9.2 km2, and 7.3 km2, respectively). By differencing a USGS digital elevation model (DEM) produced in the 1970-80s with a DEM derived from the Shuttle Radar Topography Mission (February 2000), we estimated the average thickness of the 1991-92 flow to be 13 m (ñ 5 m), which reasonably agrees with field observations of 5 m ~ 10 m. Lava-flow maps produced in this way can be used to augment field mapping and flow-hazards assessment, and to study magma-supply dynamics, and thus, to anticipate future eruptive activity. Based on the recurrence interval of recent eruptions and the results of this study, the next eruption at Westdahl may occur before the end of this decade.
DE: 8400 VOLCANOLOGY
DE: 8499 General or miscellaneous
DE: 6924 Interferometry
DE: 6969 Remote sensing
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting