昆仑山口西8.1级地震前后山西及邻区速度场和应变场的变化

The variation of the velocity field and strain field in Shanxi and its neighboring region before and after West Kunlun Mountain Pass M8.1 Earthquake

在山西及邻区，1999～2004年几乎所有的GPS站速度都小于1999～2001年，鄂尔多斯西部大多数GPS站1999-2004年的运动方向相对于1999-2001年发生了逆时针旋转。鄂尔多斯和山西中南部的NWW向运动与昆仑山口西8．1级大震断裂带以北地区的运动方向是一致的，而鄂尔多斯以南的向东运动与断裂带以南地壳的运动方向也是一致的。鄂尔多斯的逆时针旋转形成了109．0’E以西地区E—W方向的压应变。而它的逆时针旋转和太行山东部的向东伸展运动形成了109．00E以东地区E—W方向的张应变。鄂尔多斯东部和山西地区在8．1级大震后的增量应变场减弱了基本应变场E—W方向压应变的积累，而鄂尔多斯西部的增量应变场增加了E—W方向压应变的积累。

In Shanxi and its neighboring region, almost all the velocities of GPS sites in 1999-2004 are smaller than in 1999 - 2001, and the movement direction of most GPS sits in 1999-2004 showed an anticlockwise rotation to that of in 1999-2001 in the west parts of Ordos block. The NWW movement in Odors and mid - southern part of Shanxi was consistent with the movement north the fault of West Kunlun Mountain Pass MS. 1 earthquake, and the eastward movement in south Odors was also consistent with movement south the fault of the M8.1 earthquake. The anticlockwise rotation caused west 109.0°E region showing E - W direction compress strain, while the anticlockwise rotation and eastward stretching movement produced a E - W direction tensile strain state in east 109.0°E region. After the MS. 1 earthquake, the strain field in east Ordos and Shanxi area reduced the accumulation of compressive strain in basic field and the additional strain field in west parts of ordos increased the accumulation.