Coseismic Effect Simulation of Yushu M_S 7.1 Earthquake and Absolute Gravity Inspection

Using the results of aftershock relocation,inversion on seismic waves and InSAR results,and surface rupture displacements obtained by geological survey after the earthquake,this paper constructs a fault model of the Yushu M S7.1 earthquake.Based on rectangular dislocation theory in an elastic-viscoelastic layered medium,we have simulated the coseismic deformation and gravity change with gravitational effect considered.The pictures show that the absolute gravity measuring point is beside the extremum of coseismic gravity change,and the numerical value reaches 25.02×10-8m·s-2.After a discussion about the gravity changes before the earthquake and the coherence consistency between two FG-5absolute gravimeters,we think that the measured value 27.2×10-8m·s-2at Yushu station is coseismic gravity change.It's coincident with the simulation results based on dislocation theory.Therefore it is a good tool to test the near-field changes found by dislocation theory.

Using the results of aftershock relocation, inversion on seismic waves and InSAR results, and surface rupture displacements obtained by geological survey after the earthquake, this paper constructs a fault model of the Yushu Ms7. 1 earthquake. Based on rectangular dislocation theory in an elastic-viscoelastic layered medium, we have simulated the co- seismic deformation and gravity change with gravitational effect considered. The pictures show that the absolute gravity measuring point is beside the extremum of coseismic gravity change, and the numerical value reaches 25.02 x 10-Sm. s-2. After a discussion about the gravity changes before the earthquake and the coherence consistency between two FG-5 absolute gravimeters, we think that the measured value 27.2 × 10^-8 m· s^-2 at Yushu station is coseismic gravity change. It＇s coincident with the simulation results based on dislocation theory. Therefore it is a good tool to test the near-field changes found by dislocation theory.