【摘要】 利用3景Envisat雷达遥感图像,获取了2008年10月6日西藏当雄Ms6.6地震的震前及同震形变场,结果表明,震前4个多月震中区未出现显著的地壳形变,只是地震造成震中区(20 km×20 km范围)最大近0.3 m的明显变形。形变场近南北轴向对称分布,西部沉降,东部隆升。利用均匀弹性半无限位错模型和约束非线性优化算法,对断层的位错量及分布的估算表明,地震以正断破裂为主,断面最大位错达3 m,震中位于90.374°E,29.745°N,震级Mw6.35;地震发生在走向189°、倾角60°的念青唐古拉山南东麓断裂带南段的次级断层上,发震断层长12 km,宽11 km,深度9.5 km,以东西向拉伸运动为主。较浅的震源深度与断层附近的地壳热状态有关。更多还原

【Abstract】 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.更多还原