ON HORIZONTAL CRUST MOVEMENT IN NORTHEASTERN MARGIN OF QINGHAI-TIBET BLOCK WITH 2D FEM
用二维有限元研究青藏块体东北缘地壳的水平运动

By transforming the reference frame of the velocity field of horizontal movement observed by GPS during 1999-2001 and 2001-2004 in the northeastern margin of Qinghai-Tibet block and then deducting the holistic movement of the region from it,the result out velocity field reflecting relative movement in the region is gotten.On the basis of this velocity field and the optimization theory,the segmented displacement of the boundary of the studied area are deduced with two-dimensional finite element model of linear elasticity.Taking the results as boundary constraint and the velocity field of horizontal movement after transforming reference frame as the load of FEM node,the velocity field of horizontal movement in the region is simulated,the principal strain rate field and maximal shear strain rate field are calculated,the variety characteristics of the two rate fields and relation between the variety characteristics and strong earthquake preparation are analyzed.