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Title:: Research on Horizontal Crust Movement in Qinghai-Tibet Block with 2D Finite Element Method

Author(s):: JIANG Feng-yun; ZHANG Xi; ZHANG Xiao-liang; WANG Shuang-xu; GENG Xiao-ming; (Second Crust Monitoring and Application Center,CEA,Xi'an 710054,Shaanxi,China)

Keywords:: Qinghai-Tibet Block; GPS; 2D Finite Element method; optimization theory; strong earthquake

摘要:: 对1998～2003年青藏高原地区高精度GPS水平速度场成果进行参考框架的变换,获得了扣除刚性运动后的反映区域内部相对运动的水平速度场。进一步借助二维有限元技术,结合最优化原理,将变换框架后的GPS测点位移作为约束,反演区域块体边界分段位移。利用反演获得边界位移重建区域内部均匀、统一的变形场,并计算其应变率场、面膨胀率场。最后,对地质构造区域地壳变形及应变率场与强震发生部位的对应关系进行了分析。

Abstract:: Transforming the reference frame of the velocity field of horizontal movement observed by GPS from 1998 to 2003 in the Qinghai-Tibet Block and deducting the holistic movement from it,we get the velocity field reflecting relative movement in this region.On the basis of this velocity field and according to the optimization theory,we deduce the segmented displacements of the boundary of the studied area with two-dimensional finite element model of linear elasticity.Taking the results as boundary constraint,we rebuild the velocity field of horizontal movement, the strain rate field and surface dilation rate in the region. The relationship between the location of potential strong earthquake and the strain rate field and deformation field in the area of tectonic structure are analyzed.