利用1998—2011年南天山地区近90个GPS测站观测资料,获取了南天山-帕米尔地区的现今地壳运动速度场、水平应变场以及区域内主要断层的活动速率。GPS运动速率表明:1)研究区主要表现为南北向缩短挤压的运动趋势,并呈现出顺时针旋转的特征;2)最大主压应变分布自西向东递减,应变场的空间分布受区域构造的影响,与构造走向正交;3)剪应变高值区与中强地震存在密切关系,剪应变最大值集中分布在南天山西段与柯坪断裂北部地区。
An accurate crustal deformation field was derived from repeat surveys of almost 90 GPS stations carried out from 1998 to 2011 in southern Tianshan-Pamir region and present velocity field related to stable Euro-Asia plate and the distribution of crustal horizontal strain field were obtained as well. We studied the active velocity a- long the main faults in the region and the following results are achived. 1 ) The crustal shortening from south to north is the main movement trend in the southern Tianshan-Pamir region. The movement of whole area shows the charac- teristics of clockwise rotation. 2 ) The amplitude of maximum principle compressive strain decreases from west to east in the southern Tianshan - Pamir region. The regional tectonics controls the space distribution of the strain field. It shows the features that the principal stress direction basically is orthogonal to the direction of the tectonic trend in the region. 3 )There are close relation between the area of high shear strain and strong earthquakes. The maximum shear strain rate field concentrates mainly in the west of southern Tianshan, and the north area of Kalpin fault.