HR: 1340h
AN: G13A-0906    [Abstracts]
TI: GRACE Satellite Gravity Data Captures Coseismic and Postseismic Deformation from the Sumatra-Andaman Earthquake
AU: * Chen, J
EM: chen@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 West Braker Lane, #200, Austin, TX 78750,
AU: Wilson, C
EM: crwilson@mail.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 West Braker Lane, #200, Austin, TX 78750,
AU: Wilson, C
EM: crwilson@mail.utexas.edu
AF: Department of Geological Sciences, University of Texas at Austin, 1 University Station C1100, Austin, TX 78712-0254,
AU: Wilson, C
EM: crwilson@mail.utexas.edu
AF: 4Jackson School of Geosciences, 1 University Station C1100, Austin, TX 78712-0254,
AU: Tapley, B
EM: tapley@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 West Braker Lane, #200, Austin, TX 78750,
AU: Grand, S
EM: steveg@geo.utexas.edu
AF: Department of Geological Sciences, University of Texas at Austin, 1 University Station C1100, Austin, TX 78712-0254,
AU: Grand, S
EM: steveg@geo.utexas.edu
AF: Institute for Geophysics, University of Texas at Austin, 10100 Burnet Road (R2200), Bldg. 196, Austin, TX 78758-4445,
AU: Grand, S
EM: steveg@geo.utexas.edu
AF: 4Jackson School of Geosciences, 1 University Station C1100, Austin, TX 78712-0254,
AB: Recently released gravity solutions from the Gravity Recovery and Climate Experiment (GRACE) provide much improved spatial resolution, and are now of sufficient quality to observe effects of coseismic and postseismic deformation due to the Mw=9.3 Sumatra-Andaman earthquake on December 26, 2004 and its companion Nias earthquake (Mw=8.7) on 28 March 2005. The gravity field disturbance extends over 1800 km along Andaman and Sunda subduction zones, and changes with time following events. These new solutions indicate significant sea floor uplift since the Sumatra-Andaman earthquake. The estimated uplift rate is about 4 cm/yr in a broad region northwest of the epicenter centered on the Andaman-Sunda fault zone. Postseismic uplift appears strongest along the southwest side of the Andaman-Sunda fault zone, while coseismic uplift is strongest near the epicenter. In the subduction zone (northeast of the Andaman and Sunda fault zone), both coseismic decreases in gravity and postseismic increases appear strongest within a few hundreds km of the fault. When interpreted as uplift, GRACE estimates appear consistent with predicted and geodetically observed viscoelastic relaxation effects.
DE: 1209 Tectonic deformation (6924)
DE: 1217 Time variable gravity (7223, 7230)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7240 Subduction zones (1207, 1219, 1240)
SC: Geodesy [G]
MN: 2007 Fall Meeting