HR: 0830h
AN: G21B-0271    [PDF]
TI: Post-Seismic Deformation from Geodetic Observations Following the 1999 M7.1 Hector Mine Earthquake
AU: * Austin, K
EM: austink@usc.edu
AF: University of Southern California, Dept. of Earth Sciences 3651 Trousdale Pkwy., Los Angeles, CA 90089-0740 United States
AU: Owen, S
EM: owen@usc.edu
AF: University of Southern California, Dept. of Earth Sciences 3651 Trousdale Pkwy., Los Angeles, CA 90089-0740 United States
AB: The 16 October 1999 Mw7.1 Hector Mine earthquake ruptured only 20 km to the east of the 1992 Mw7.3 Landers earthquake in a region of the Mojave desert that experiences large earthquakes approximately every 10,000 years. While it is well-known that major earthquakes cause aseismic deformation transients, the mechanisms behind this deformation are the subject of some debate. For this reason there has been a concentrated effort to collect both survey-mode and continuous GPS measurements of the postseismic deformation following the Hector Mine rupture. The currently available geodetic data measures ground deformation with unprecedented spatial and temporal resolution, however it is important to remove seasonal signals from the continuous GPS time series. The quality of the time series at each of these sites varies significantly, but by carefully analyzing the spatial and temporal distribution of the vertical deformation, we can potentially resolve the rheology of the lower crust, and whether strain is accommodated by localized deformation, or a more distributed viscous flow (Pollitz et al., 2001). A GIPSY-OASIS point-positioning approach with ambiguity resolution is used followed by a principal component analysis to remove the time-correlated noise in the time series. The final time series are compared to currently available models to determine the likely processes at work. Stations within the observed network display both horizontal and vertical postseismic signals which decay rapidly in the first few months following the earthquake.
DE: 1200 GEODESY AND GRAVITY
DE: 1242 Seismic deformations (7205)
DE: 7200 SEISMOLOGY
DE: 8159 Rheology--crust and lithosphere
SC: Geodesy [G]
MN: 2003 Fall Meeting