基于GPS速度场的青藏块体东北缘应变场分析

Strain Field Analysis of Northeast Margin of Qinghai-Tibet Block Based on GPS Velocity Fields

利用2004～2013年GPS速度场数据,分析青藏块体东北缘的应变场和剖面应变积累特征。结果显示：1）稳定的阿拉善地块及鄂尔多斯地块分别阻挡了祁连山断裂带与贺兰山构造区分别向NE、E方向的物质迁移;2）主压应变率、最大剪应变率高值区均分布在祁连山构造带东段、海原断裂东段至六盘山断裂西段,面膨胀率压性高值区主要在祁连山构造带东段,3）祁连山断裂东段显示为以压性为主、兼具左旋走滑,海原断裂东段至六盘山断裂西段则表现为以左旋走滑为主、压性为辅的相对运动特征。

This article analyzed the strain field and sectional strain accumulation characteristics about Qinghai-Tibet block with the 2004-2013 GPS velocity field data.The results show that：1）The stable Alashan and Ordos blocks stop the migration for northeast on the Qilian and Helan faults for east;2）The high value areas of principal compressive strain rate and the maximum shear strain rate distribute the eastern of Qilianshan faults and from the eastern of Haiyuan fault to the western of Liupanshan fault,the high value areas of compressibility surface expansion distributes at the eastern of Qilianshan faults;3）The relative movement features are mainly compression and both left-lateral strike-slip of the eastern of Qilianshan faults,mainly left-lateral strike-slip and both compreesion from the eastern of Haiyuan fault to the western of Liupanshan fault.