HR: 1340h
AN: G13A-0923    [Abstracts]
TI: Postseismic deformation of the 2001 Bhuj earthquake from GPS, Gravity and InSAR data
AU: * V., C D
EM: dcshaker@seismo.berkeley.edu
AF: Univ. of California, Berkeley Seismological laboratory, Berkeley, CA 94720-4760, United States
AU: Bürgmann, R
EM: burgmann@seismo.berkeley.edu
AF: Univ. of California, Berkeley Seismological laboratory, Berkeley, CA 94720-4760, United States
AU: Jade, S
EM: sridevi@cmmacs.ernet.in
AF: CMMACS, CSIR, Bangalore, KAR 560 037, India
AU: Kato, T
EM: teru@eri.u-tokyo.ac.jp
AF: Univ. of Tokyo, EPRC, ERI, TOKYO, TOK 113-0032, Japan
AU: Likhar, S
EM: z01404004@iitb.ac.in
AF: IIT, Powai, MUMBAI, MAH 400076, India
AU: Reddy, D C
EM: cdreddy@iigs.iigm.res.in
AF: IIGM, Plot No. 5, Sector-18 Kalamboli Highway, NAVI MUMBAI (W), MAH 410218, India
AU: Schmidt, D A
EM: das@uoregon.edu
AF: University of Oregon, 1272 University of Oregon, Eugene, OR. 97403-1272, United States
AU: S., S P
EM: sunilps@iigs.iigm.res.in
AF: IIGM, Plot No. 5, Sector-18 Kalamboli Highway, NAVI MUMBAI (W), MAH 410218, India
AB: Postseismic deformation phenomena have been observed following many major earthquakes and visco-elastic relaxation of the lower crust and upper mantle often dominates the intermediate-scale (one to several fault lengths) deformation patterns. Other relaxation processes, namely discrete afterslip and poroelastic rebound may also contribute to the observed deformation, especially in the near field and earliest phase of the postseismic transient. GPS measurements, observations of gravity field changes and InSAR range-change data collected following the Mw 7.6 2001, Bhuj earthquake provide a unique opportunity to probe lithospheric rheology in an intra-plate setting. The transient deformation rates following the Bhuj earthquake are substantially lower (< 3 cm of horizontal motion in first two years) than those observed following several recent inter-plate earthquakes, suggesting that the event is underlain by relatively strong lithosphere. We model the spatial deformation data assuming visco-elastic relaxation of the lithosphere, using constraints on geometry and rupture parameters on the source fault from earlier studies. We also explore contributions from and tradeoffs with afterslip and poroelastic rebound mechanisms. Our physical model of the visco-elastic deformation elucidates the nature of deep relaxation in the visco-elastic lower crust-upper mantle layers resulting from the Bhuj earthquake stress perturbation.
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 6924 Interferometry (1207, 1209, 1242)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Geodesy [G]
MN: 2007 Fall Meeting