CHARACTERISTICS OF PRESENT CRUSTAL DEFORMATION AND DISTRIBUTION OF STRAIN FIELD IN SOUTHERN TIANSHAN-PAMIR REGION
南天山-帕米尔现代地壳形变特征与应变场分布

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 along 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 characteristics 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.