S. Kuhn and M. Ramsey, Department of Geology and Planetary Science, 200 SRCC Building, University of Pittsburgh, Pittsburgh, PA, USA, 15260

Satellite remote sensing has played an integral part in monitoring and characterizing active volcanic processes or in aiding to identify preliminary stages of activity. The Advanced Spaceborne Thermal Emission Reflectance Radiometer (ASTER) is a high resolution multispectral imager ideal for discerning these physical variations on the surface of active lava domes. The five bands of thermal infrared data at 90 meter spatial resolution can be used to retrieve accurate temperature as well as surface emissivity data. These data provide a quantitative means of estimating glass and vesicle distribution on a changing dome, which can then be used to infer internal processes within the magmatic system. Much of the previous work of IR spectroscopy and silicic flows has focused on model validation using airborne data collected over inactive lava domes. For the first time, this study analyzes data from an actively-deforming silicic dome on the island of Montserrat. Six nighttime ASTER scenes of the Soufrihre Hills volcanic dome have been chosen for this analysis. These data cover the entire extent of the dome, show the presence of thermal infrared anomalies and pyroclastic flow activity, as well as contain a relative lack of cloud cover. The linear spectral deconvolution technique utilized in this study employs the spectral signatures of two known end-member materials (glass and vesicles), to resolve the unknown spectrum into areal abundances of each end-member. This technique produces surface maps of the distribution of vesiculated rock across the dome, over time.

Montserrat Volcano Observatory (MVO) weekly reports from 1999 to present (available online) were also ingested into a multi-parameter, searchable database. These data detail specific volcanic activity and were compared against the ASTER data. The database fields include SO2 flux, high temporal resolution weather satellite-derived radiance measurements, description of dome growth and collapse, and intensities of pyroclastic flows, rockfalls, fumarolic activity, and seismic activity. This database provides a unique cross-reference for the interpretation of the spaceborne data, as well as highlighting observable trends in each of the volcanic activity types. Results from this study have provided a better understanding of the capabilities of the ASTER instrument to accurately describe active dome processes and to characterize these processes both quantitatively and statistically. This knowledge can be applied to other volcanoes with active domes in order to study indicators of future dome growth/collapse, the generation of hazardous pyroclastic activity, as well as the transition from effusive to explosive dome growth.

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Submitted: Annual Meeting of the Geological/Mineralogical Association of Canada
Date: May 12 - 14, 2004