The mechanism of the vertical uplift of crust in the west of Longmenshan before Wenchuan Ms8. 0 earthquake has been debated through constructing the 2-D FEM model for the profile across Longmenshan fault, which is based on the velocity field that had calculated from the GPS observations and the result of seismic tomography obtained by Wu Jiangping et al. In addition, the effect of crustal inhomogeneity on the vertical uplift has been discussed as well. We concluded that the existence of the low velocity anomaly in the low cust below the front of Longmenshan fault play a key role, and vertical uplift is likely caused by both the curst shorten of the westen Longmenshan and the differential uplift between Chuanxi pletau and Sichuan basin.%结合流动GPS观测速度场及层析成像结果,构建跨龙门山断裂剖面的二维有限元分层模型,分两种情况讨论汶川地震前龙门山前缘地壳垂直隆升的物理机制,以及中、下地壳软物质垂向和横向的不均匀性对地壳隆升作用的影响.分析认为:川西高原相对四川盆地的差异抬升和龙门山以西地壳缩短的共同作用是汶川地震震前龙门山前缘地壳垂直隆升的可能原因.
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