基于幂函数计算汶川同震地壳水平应变

Calculation of Horizontal Strain of Coseismic Crust in Wenchuan Based on Power Function

基于幂函数模型,根据最小二乘原理构建了地壳运动速度场模型,在此基础上对速度场模型求导获取地壳水平应变的计算公式。结合2008年汶川地震同震的GPS(Global Position System)观测资料,计算了该区域地壳水平应变,结果表明:汶川地区的主应变空间分布呈现出不均匀性,主应变与龙门山断裂延伸走向接近垂直,以主压应变,在汶川以南和以北研究区域,呈现出拉张应变强于挤压应变的状况。汶川恰好处于北部最大剪应变区与南部最大剪应变区的过渡区域。

The velocity field model of crustal movement is constructed by the principle of least squares based on power function,and on this basis,the computational formula of crustal horizontal strain is obtained by the derivation of velocity field model.The crustal horizontal strain in this region is calculated by the observation data of coseismic GPS（Global Position System）from Wenchuan earthquake of 2008.Results show that the spatial distribution of the main strain in Wenchuan area is inhomogeneous,and the main strain is close to the vertical with the extension of Longmenshan fault.With the main pressure strain,in the south and north of Wenchuan area,the tensile strain is stronger than the extrusion strain.Wenchuan area is in the transition zone of maximum shear strain between the northern region and the southern region.