中国西部现今地壳形变与地震活动特征

以1999-2004年间中国西部地区近650个GPS站点的观测资料为基础，采用二维“高张力样条”函数内插算法获得了连续地壳形变场。结果表明，相对于稳定欧亚参考框架，中国西部现今地壳运动西强东弱，北向运动从西向东逐渐减弱，东向运动逐渐增强，青藏高原东缘及附近地区是东向运动的消减区带；主应变从西向东由压缩应变转变为拉伸应变；最大剪应变主要位于喜马拉雅地块及其东部地区；中国西部地区地震活动在空间分布上似乎集中发生在印度板块北东向挤压欧亚板块的两条共扼带内，与地壳形变场有一定对应关系，地壳形变的高应变率区为中强地震多发地带。

Characteristics of present-day crustal deformation and seismicity in western China

Based on the measurements of about 650 GPS stations in Western China observed in the period from 1999 to 2004,it uses the "spline in tension" interpolation method to obtain a continuous velocity field of crustal movement.The results indicate that in a stable Eurasia reference frame,the crustal movement in the western part of the region is larger than that of the eastern part.From West to East,the north component of the movement gradually becomes smaller,and the east component gradually becomes higher.The east edge of the Tibet Plateau and its vicinity are areas with declined east movement.The principal strain is gradually changing from compression in the western area to extension in the eastern area.The high shear strain rates are located in the Himalayan block and its east regions.It seems that many earthquakes happened along two conjugate zones in Chinese mainland produced by the convergence between the India and Eurasia during the period from 1995 to 2006.The seismic activity is corresponding to crustal deformation rate,i.e.more earthquakes occurred in the regions with higher strain rates.