青藏高原东北缘主要断裂滑动速率及其动力学意义

本文利用青藏高原东北缘地区1991—2015年的GPS速度场资料, 基于弹性球面块体模型获得了区域活动断裂的滑动速率, 并讨论了断裂滑动速率分配的动力学意义。 反演结果表明, 青藏高原东北缘地区主要块体以北东向并兼顺时针旋转运动为主; 区域断裂平均闭锁深度为17 km; 另外, 各主要断裂滑动速率也不尽相同。 其中, 阿尔金断裂、 东昆仑断裂左旋走滑速率为10～12 mm/a, 祁连—海原断裂左旋走滑速率为3～5 mm/a, 鄂拉山断裂、 拉脊山断裂右旋走滑速率为1～3 mm/a。 阿尔金断裂、 祁连—海原断裂、 东昆仑断裂的走滑速率被其端部的山脉隆起和逆冲断裂所吸收和转换, 鄂拉山断裂和拉脊山断裂则起到了调节块体间运动平衡的作用。

Slip Rates of the Major faults in the Northeastern Tibetan Plateau and Their Geodynamic Implications

We used GPS data in the northeastern margin of the Qinghai-Tibet Plateau from 1991 to 2015 to obtain slip rates along active faults based on the elastic block model, and then discussed the dynamic implication of the pattern. Our results show that most of the blocks in the study area move northeastward and rotate clockwise, the average lock depth of fault is 17 km, and the major active fault zones also have large difference in their velocity. For example, the left-lateral strike-slip rate of the Altyn and the East Kunlun fault is 10～12 mm/a. The left-lateral strike-slip rate of the Qilian-Haiyuan fault is 3～5 mm/a. The right-lateral strike slip rate of the Elashan and Lajishan fault is 1～3 mm/a. The strike-slip rates of the Altyn fault, the Qilian-Haiyuan fault and the East Kunlun fault are absorbed and converted by the mountain uplift and reverse thrust faults at the ends of the fault, the Elashan fault and the Lajishan fault play the role of adjusting blocks.