????Ms6.6?????InSAR??????λ????

????3??Envisat?????????,?????2008??10??6?????????Ms6.6??????????????α?,????????????4????????????δ?????????????α?,?????????????????20 km??20 km??Χ??????0.3 m????????Ρ??α??????????????????????????????????????t???????????λ???????????????????????????λ?????????????????????????????????????????????λ???3 m, ????λ??90.374??E, 29.745??N????Mw6.35??????????????189?????60????????????????′???????ε?μ?????????????12 km,??11 km,???9.5 km???????????????????????????????????????????????й??

STUDY ON DISLOCATION INVERSION OF Ms6.6 DAMXUNG EARTHQUAKE AS CONSTRAINED BY InSAR MEASUREMENT

Three scenes Envisat-1 images from ESA were used to derive the pre-seismic and coseismis deformation interfereograms caused by the Damxung Ms6.6 earthquake on Oct. 6, 2008, constrained by InSAR. The results indicate that InSAR could not detect notable crustal motion more than 4 months before the event which caused distinct displacement in an area of 20 km×20 km with a maximum LOS change about 0.3 m. The deformation field was symmetrically distributed and separated by a NS axis, where the west subsided and the east rose. We used a linear elastic dislocation model in half space and nonlinear constraint optimized algorithm to estimate the dislocation value and distribution of the fault. The results indicate that the epicenter locates at E90.374°, N29.745° with a seismic moment tensor Mw6.35. The earthquake is dominated by a normal fault fracture with the maximum slip of 3m on the 12 km×11 km rupture surface striking S189°W, dipping 60°to NW at the bottom of 9.5 km, located at a sub-fault of the southeastern piedmout of the Nyainqentanglha Mountains. The seismic fault extensionally moves along EW. The shallow depth of epicenter is related to crust thermal status of seismic region.