HR: 0830h
AN: V51F-0350    [PDF]
TI: Low-level Volcano Thermal Anomaly Survey of Northern Pacific Volcanoes Using Night Time ASTER TIR
AU: * Wessels, R
EM: rwessels@usgs.gov
AF: U.S. Geological Survey Alaska Volcano Observatory, 4200 University Dr., Anchorage, AK 99508 United States
AU: Ramsey, M
EM: ramsey@ivis.eps.pitt.edu
AF: Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, PA 15260 United States
AU: Schneider, D
EM: djschneider@usgs.gov
AF: U.S. Geological Survey Alaska Volcano Observatory, 4200 University Dr., Anchorage, AK 99508 United States
AU: Dehn, J
EM: jdehn@gi.alaska.edu
AF: Geophysical Institute/Alaska Volcano Observatory, University of Alaska Fairbanks, Fairbanks, AK 99775 United States
AB: The Alaska Volcano Observatory (AVO) monitors northern Pacific volcanoes for major thermal anomalies by analyzing frequent Thermal Infrared (TIR) images from the Advanced Very High Resolution Radiometer (AVHRR) and Moderate-resolution Imaging Spectroradiometer (MODIS) sensors at least twice per day. Although 1 km resolution AVHRR and MODIS data have been very useful in detecting large and/or high-temperature thermal signatures such as lava flows, domes, pyroclastic flows, higher spatial resolution is needed to observe and quantify small and/or lower temperature thermal features such as fumaroles. We are currently evaluating all available night time TIR scenes acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) L1B over Alaskan (475 scenes) and Kamchatka - Kurile volcanoes (606 scenes). While the current archive spans June 2000 to present, most of the data were collected during the last two years. Night time ASTER data over volcanic targets typically provides 5 TIR bands with 90 meter spatial resolution and 6 Shortwave Infrared (SWIR) bands with 30 meter resolution. The ASTER L1B data were first scanned for warm pixels using an application that records the maximum radiance values for all available bands in each image. The scene maximum radiance results were then sorted in order of decreasing radiance. Next, each scene was manually reviewed for thermal anomalies co-located with volcanoes. All scenes with volcanic thermal anomalies were then submitted for ASTER Level 2 Surface Kinetic Temperature processing. The Surface Temperature product provides an estimate of the surface temperature for each of the five ASTER TIR bands. The pixel temperatures are then extracted for each thermal anomaly Our ongoing survey of the ASTER TIR data has revealed many small or low temperature thermal features at several volcanoes in Alaska and Kamchatka. Few of these features were recognized in the daily AVHRR and MODIS reports because the signal was too small to detect easily. The ASTER TIR observations are currently being compared to published and unpublished field temperature measurements. These new observations will be used to assess recent activity as well as add to AVO's database for ongoing activity.
DE: 8419 Eruption monitoring (7280)
DE: 8424 Hydrothermal systems (8135)
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting