HR: 1340h
AN: G53B-0888    [Abstracts]
TI: Monitoring Mount St. Helens activity by airborne and space-based laser altimetry elevation measurements
AU: * Carabajal, C C
EM: claudia@bowie.gsfc.nasa.gov
AF: NVI Inc.@NASA Goddard Space Flight Center, Space Geodesy Laboratory - Code 697, Greenbelt, MD 20771 United States
AU: Harding, D J
EM: David.J.Harding@nasa.gov
AF: NASA Goddard Space Flight Center, Planetary Geodynamics Laboratory - Code 698, Greenbelt, MD 20771 United States
AU: Haugerud, R A
EM: rhaugerud@usgs.gov
AF: U.S. Geological Survey, University of Washington Dept. Earth and Space Sciences Box 351310, Seattle, WA 98195 United States
AB: Renewed volcanic activity at Mount St. Helens provides an unusual opportunity to devise and test methods for better understanding and predicting eruptions. One of the main techniques used to monitor volcanic activity involves the measurement of surface deformation. Technological developments in airborne and space-based laser altimetry enables very accurate measurements of topographic change that are useful in the study of potentially hazardous volcanoes. Complimenting in-situ GPS measurements of Mount St. Helens deformation, airborne laser scanning surveys and Ice, Cloud and land Elevation Satellite (ICESat) profiles have provided elevation change data over a much broader area, at times inaccessible by other means, with decimeter vertical accuracy. Deformation can be documented and mapped accurately, dimensions of the uplift can be estimated, and improved volcanic hazards forecast models can be created. Airborne laser scanning technology has been used by U.S. Geological Survey (USGS) and NASA scientists to study and analyze changes in the surface elevation of the crater, using high-resolution (~ 2 m) surveys from before and after the onset of activity in September, 2004. A 2003 survey was re-mapped, after the onset of new activity, on Oct. 4th, 2004 and later on November 20th, 2004, documenting formation of a new dome on the south side of the crater dome formed in the 1980s. In addition, ICESat profiles acquired in October-November, 2004 and May, 2005, after the onset of St. Helens' activity, provide the first laser altimeter measurements of a deforming volcano from space. The geolocation accuracy of these ICESat profiles have been assessed using profile matches to USGS 10 m resolution DEMs and waveform matching to simulated waveforms at every footprint location, using the high resolution airborne laser scanning data and a model of the ICESat instrument. We will present perspectives of Mount St. Helens' surface deformation as seen by both laser altimetry techniques.
DE: 1200 GEODESY AND GRAVITY
DE: 1209 Tectonic deformation (6924)
DE: 1243 Space geodetic surveys
DE: 1294 Instruments and techniques
DE: 8419 Volcano monitoring (7280)
SC: Geodesy [G]
MN: Fall Meeting 2005