An earthquake (33.2°N, 96.6°E, Ms=7.1) struck Yushu Zang Autonomous Prefecture, Qinghai Province of China on 14 April 2010, which was triggered by the strong activity of Ganzi-Yushu Fault. And the Ganzi-Yushu Fault which distributes mostly in Qinghai-Tibet Plateau orientates NW direction. Also it is the south boundary of Bayanhar Belt together with Xianshuihe Fault, and they are left step nearby Ganzi area. From regional geological results and aero-photos in combination with detailed field study, the ground ruptures show a series of compressional bumps and tension fissures, therefore we can draw a conclusion that all these characteristics reflect the kinematics properties of left-lateral and strike-slip fault. Then D-InSAR (Differential Synthetic Aperture Radar Interferometry) technique is used to acquire the co-seismic deformation field, it gives the spatial distribution of the ground rupture zone of the earthquake in the one hand, and in the other hand the surface displacement in LOS direction was derived and the location of the source fault was determined. According to the analysis of the co-seismic deformation field, it also shows typical characteristics of left-lateral and strike-slip fault. Geodetic inversions are a useful tool for estimating source parameters of earthquakes. Thereby based on the dislocation of co-seismic and the fault plane model, we got the simulation co-seismic deformation field, and simultaneously the fault's attitude is obtained by the boundary element inversion method. There is evident surface rupture along the main shock's causative in the interferogram, and the co-seismic deformation field is about 75km in length and 55km in width. The seismogenic fault of the main shock strikes about N61°W, dips NE, and inverted fault dipping direction and dip-slip are consistent with field investigation. During the process of simulation, we adopted the different fault models respectively. Through the comparison and analysis of different simulation results, we prefer the segmentation fault model. The maximum dislocation in LOS of the earth surface is 0.57m, the seismic moment is about 2.86×1019Nm, which equals to a Mw=6.9 earthquake.
ZHOU Huifang, ZHANG Jingfa, HU Leyin, LUO Yi
. Co-seismic Deformation Field and Parameters Inversion of the Yushu Earthquake from InSAR[J]. Journal of Geo-information Science, 2011
, 13(3)
: 418
-423
.
DOI: 10.3724/SP.J.1047.2011.00418
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