A.J. Carter, Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, PA

M. Ramsey, Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, PA

A. Belousov, Institute of Marine Geology and Geophysics, Nauki str, 1, Yuzhno-Sakhalinsk, Russia

R. Wessels, U.S. Geological Survey, Alaska Science Center, Alaska Volcano Observatory, Anchorage, AK

J. Dehn, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK

Based on seismic observations, a large explosion occurred at the summit of Bezymianny Volcano, Kamchatka Peninsula, Russia on 11 January 2005. This prompted the acquisition of fifteen (four day and eleven night) Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite images of the area over the next eight months. These data provided an unprecedented time series of high-resolution thermal infrared (TIR) data of the volcano and its deposits, as an initial test of the new ASTER rapid-response program (in conjunction with the Alaska Volcano Observatory). A field campaign was undertaken in August 2005 to monitor and interpret recent activity using both ground and airborne Forward Looking Infrared Radiometers (FLIR) surveys. Airborne visual and FLIR observations revealed that the morphology of the summit lava dome had changed significantly since August 2004. The dome currently contains a collapse crater roughly 200 m in diameter and a small viscous lava lobe that drapes the crater rim. Stepped scarps within the new summit crater suggest a partial collapse mechanism of formation rather than a purely explosion-related origin. Activity in 2005 also created a v-shaped notch in the southern part of the dome, which had observable high temperature fumarolic activity and may be an area of future structural weakness. The January explosion produced a plan-view mushroom shaped deposit branching from the summit that pooled against the 1956 crater wall, with some material travelling up to 3 km to the southeast away from the horseshoe-shaped crater. The FLIR acquisitions detected temperatures above 120C within these summit deposits, particularly within oval-shaped collapse pits, likely created from deposition of the hot material onto snow and ice. The slow cooling rate is most likely a function of the deposit thickness by the crater rim and the thermal insulation of the surrounding rocks. Observed ASTER thermal anomalies in combination with FLIR and standard photography suggest the events beginning 11 January resulted in the formation of a summit collapse crater, a small viscous lava flow, and a dense block and ash flow that moved initially to the northwest, and then spread out, following the lowest elevation areas within the crater rim. The sequence of these events is still under study using scientific observations made from FLIR and ASTER data.

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Submitted: American Geophysical Union Fall Meeting
Date: December 5 - 9, 2004