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GEOPHYSICAL RESEARCH LETTERS, VOL. 32, L19305, doi:10.1029/2005GL024112, 2005

Monitoring eruptive activity at Mount St. Helens with TIR image data

R. G. Vaughan

Jet Propulsion Laboratory, Pasadena, California, USA


S. J. Hook

Jet Propulsion Laboratory, Pasadena, California, USA


M. S. Ramsey

Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA


V. J. Realmuto

Jet Propulsion Laboratory, Pasadena, California, USA


D. J. Schneider

Alaska Volcano Observatory, U.S. Geological Survey, Anchorage, Alaska, USA


Abstract

Thermal infrared (TIR) data from the MASTER airborne imaging spectrometer were acquired over Mount St. Helens in Sept and Oct, 2004, before and after the onset of recent eruptive activity. Pre-eruption data showed no measurable increase in surface temperatures before the first phreatic eruption on Oct 1. MASTER data acquired during the initial eruptive episode on Oct 14 showed maximum temperatures of ∼330°C and TIR data acquired concurrently from a Forward Looking Infrared (FLIR) camera showed maximum temperatures ∼675°C, in narrow (∼1-m) fractures of molten rock on a new resurgent dome. MASTER and FLIR thermal flux calculations indicated a radiative cooling rate of ∼714 J/m2/s over the new dome, corresponding to a radiant power of ∼24 MW. MASTER data indicated the new dome was dacitic in composition, and digital elevation data derived from LIDAR acquired concurrently with MASTER showed that the dome growth correlated with the areas of elevated temperatures. Low SO2 concentrations in the plume combined with sub-optimal viewing conditions prohibited quantitative measurement of plume SO2. The results demonstrate that airborne TIR data can provide information on the temperature of both the surface and plume and the composition of new lava during eruptive episodes. Given sufficient resources, the airborne instrumentation could be deployed rapidly to a newly-awakening volcano and provide a means for remote volcano monitoring.

Received 19 July 2005; accepted 9 September 2005; published 14 October 2005.

Index Terms: 3641 Mineralogy and Petrology: Extrusive structures and rocks; 8419 Volcanology: Volcano monitoring (7280); 8485 Volcanology: Remote sensing of volcanoes; 8494 Volcanology: Instruments and techniques.

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Citation: Vaughan, R. G., S. J. Hook, M. S. Ramsey, V. J. Realmuto, and D. J. Schneider (2005), Monitoring eruptive activity at Mount St. Helens with TIR image data, Geophys. Res. Lett., 32, L19305, doi:10.1029/2005GL024112.