Deciphering Silicic Dome Emplacement Processes in the North Pacific: Quantitative Analyses of High Resolution Satellite and Field-Based Data

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

Dehn, J., Adleman, J.N., Larsen, J.F., Geophysical Institute/Department of Geology and Geophysics, University of Alaska Fairbanks, 99775

McGimsey, R.G., Neal, C.A., Wessels, R.L., U.S. Geological Survey, Alaska Volcano Observatory, Anchorage, AK 99508

Although volumetrically small in comparison to other lava compositions and types of extrusive products, intermediate to silicic domes preserve an enormous quantity of information on the pressure, temperature, flow rate and degassing state of the lava. Remotely acquired data of active domes also provides insights into the duration of continued lava extrusion and the hazards of the volcano/dome system. Numerous techniques for the mapping, monitoring and modeling of lava domes have been developed, with much of that work focused on older inactive domes. However, with the recent launch of new higher spatial resolution satellites imaging in multiple wavelength regions, it is now possible to collect new and highly detailed data of active domes. One of the most promising satellite instruments for volcanology is the ASTER instrument launched by NASA in late 1999. Because it is the first spaceborne sensor to acquire high spatial resolution data from the visible to thermal infrared wavelength region and has the ability to generate digital elevation models, it is particularly useful for numerous aspects of volcanic remote sensing. For example, the multispectral thermal infrared (TIR) capability of ASTER is critical for monitoring low temperature anomalies and mapping both chemical and textural variations on the dome surfaces. However, the ability to derive this level of quantitative information currently relies on accurate field based data collection, laboratory modeling and the development of new computer-based tools.

ASTER data have been analyzed in detail for numerous silicic lava domes in the Aleutian-Kamchatkan Arc system over the past three years. These domes have varied from the vigorously-active andesitic domes at Bezymianny and Sheveluch volcanoes to the dacitic dome field at Black Peak volcano, emplaced following the caldera forming eruption ~4,600 years ago. For the active domes at the Kamchatkan volcanoes, ASTER TIR data were used to monitor eruptions and map the volcanic products. The thermal anomalies vary significantly from Bezymianny to Sheveluch and are being used to derive textural variations on the domes and pyroclastic flow deposits. A field campaign to the Black Peak domes in the summer of 2003 provided one of the first detailed mapping opportunities for this volcano and the chance to collect data on the composition, surface texture, topography and stratigraphy of the domes. These data are now being used to better constrain the modeling of the active domes in preparation for a field campaign to Kamchatka in 2004. In summary, the high spatial and spectral resolution of the ASTER data are extremely useful in discrimination of small surface targets in addition to providing enhanced volcanic mapping capabilities.

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Submitted: American Geophysical Union Fall Meeting
Date: December 8 - 12, 2003