The surface coseismic deformation and source parameters research of the Xizang Gaize earthquake based on the InSAR technology

On 9 January, 2008, the Mw 6.4 earthquake occurred in Gaize, central Tibet of China, then the largest aftershock Mw 5.9 followed on 16th of January. Firstly, we derive the co-seismic deformation field with Synthetic Aperture Radar. The results show an asymmetric deformation pattern both mainshock and aftershock with normal faulting on a NE-striking fault plane. Then we invent for the geometry and the slip-distribution on thedouble-fault models. The result shows that the inverted hypocenter location of Mw 6.4 mainshock and Mw 5.9 aftershock are at 85.30±0.03°E/32.44±0.03°N and 85.27±0.01°E/32.46±0.02°N with strikes of 213.31° and 201°, and with dips of 56° and 54°, respectively. The mainshock upper side is about 2.9km from ground surface, the average slip is 0.74m and the maximum slip is about 2.32m occurring at depth of 7.92km under ground surface, and the average rake over the slipping area is −65.4°, the released scalar moment is 2.19×10¹⁸ Nm; The aftershock upper side is about 1.6km from ground surface, the average slip is 0.87m and the maximum slip is about 1.12m occurring at depth of 4.13km under ground surface, and the average rake over the slipping area is −75.0°, the released scalar moment is 1.41×10¹⁸ Nm.