HR: 16:00h
AN: V24A-01 INVITED     [Abstracts]
TI: Airborne thermal infrared imaging of the 2004-2005 eruption of Mount St. Helens
AU: * Schneider, D J
EM: djschneider@usgs.gov
AF: U.S. Geological Survery, Alaska Science Center Alaska Volcano Observatory, Anchorage, AK 99508 United States
AU: Vallance, J W
EM: vallance@usgs.gov
AF: U.S. Geological Survey, Cascades Volcano Observatory, Vancouver, WA 98683 United States
AU: Logan, M
EM: mlogan@usgs.gov
AF: U.S. Geological Survey, Cascades Volcano Observatory, Vancouver, WA 98683 United States
AU: Wessels, R
EM: rwessels@usgs.gov
AF: U.S. Geological Survery, Alaska Science Center Alaska Volcano Observatory, 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
AB: A helicopter-mounted forward-looking infrared imaging radiometer (FLIR) documented the explosive and effusive activity at Mount St. Helens during the 2004-2005 eruption. A gyrostabilzed gimbal controlled by a crew member houses the FLIR radiometer and an optical video camera attached at the lower front of the helicopter. Since October 1, 2004 the system has provided an unprecedented data set of thermal and video dome-growth observations. Flights were conducted as frequently as twice daily during the initial month of the eruption (when changes in the crater and dome occurred rapidly), and have been continued on a tri-weekly basis during the period of sustained dome growth. As with any new technology, the routine use of FLIR images to aid in volcano monitoring has been a learning experience in terms of observation strategy and data interpretation. Some of the unique information that has been derived from these data to date include: 1) Rapid identification of the phreatic nature of the early explosive phase; 2) Observation of faulting and associated heat flow during times of large scale deformation; 3) Venting of hot gas through a short lived crater lake, indicative of a shallow magma source; 4) Increased heat flow of the crater floor prior to the initial dome extrusion; 5) Confirmation of new magma reaching the surface; 6) Identification of the source of active lava extrusion, dome collapse, and block and ash flows. Temperatures vary from ambient, in areas insulated by fault gouge and talus produced during extrusion, to as high as 500-740 degrees C in regions of active extrusion, collapse, and fracturing. This temperature variation needs to be accounted for in the retrieval of eruption parameters using satellite-based techniques as such features are sub-pixel size in satellite images.
DE: 8419 Volcano monitoring (7280)
DE: 8485 Remote sensing of volcanoes
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005