基于GPS观测的东昆仑断裂玛沁段滑动速率和地壳形变研究

The fault slip rate and regional crustal deformation can provide valuable insights into the kinematics of the Tibet Plateau and regional seismic hazard assessment. The East Kunlun fault, which runs across the northeastern Tibet, plays an important role in the tectonic deformation process of the Plateau. However, due to the lack of dense geodetic observations,there almost has no study about the fault slip rate of the east segment of the Kunlun fault. In this research, we will acquire local crustal deformation field near Maqin segment of the East Kunlun fault, based on dense GPS data accumulated by our institute combined with GPS data in this area released by other facilities. The crust deformation induced by the co- and post-seismic effect of strong earthquakes occurred in and near the research area, will be modelled and subtracted from the obtained GPS velocity field. Constrained by the GPS data mentioned above, we will analyse the crustal deformation and invert the fault slip rate/locking depth by considering the fault geometry, lateral inhomogeneity of the medium. This study will lay significant foundation for further kinematic studies and regional seismic hazard assessment.

断层的滑动速率和区域地壳形变对认识青藏高原的运动学模式和区域地震危险性评估具有重要意义。位于青藏高原东北缘的东昆仑断裂在青藏高原的构造变形中扮演了重要角色,但由于密集形变观测资料的缺乏，到目前为止对东昆仑断裂东段的滑动状态和形变特征的研究还不多见。本申请项目拟利用本单位积累的跨断层密集GPS资料，结合已有的区域形变资料获取东昆仑断裂玛沁段的跨断层形变剖面,模拟并分离研究区域及周边强震的同震及震后效应的影响，在此基础上考虑断层几何构型和两侧介质属性差异等因素，反演断层的滑动速率/锁闭深度并分析区域形变特征,为区域地震危险性评估和青藏高原的运动学研究提供依据.

断层的滑动速率和闭锁深度对研究其孕震背景合区域地震危险性评估具有重要意义。本项目通过搜集跨断层密集GPS 资料，结合已有的区域形变资料获取东昆仑断裂玛沁段的跨断层形变剖面,模拟并分离了研究区域及周边强震的同震及震后效应的影响，反演了断层的滑动速率/锁闭深度并分析区域形变特征。结果显示，东昆仑断裂东段现今的滑动速率 9.5 mm/y， 闭锁深度为14.5 km。我们的滑动速率结果与地质学结果基本一致，闭锁深度也与区域地震活动性接近。另外，我们发现历史强震的震后粘弹松弛效应对现今地壳变形场仍有明显的影响。这一项目的结果能为区域地震危险性评估和青藏高原的运动学研究提供依据. 本项目共发表论文SCI论文5 篇，超过了计划的指标。另外， 本项目还部分资助了一名博士生和一名硕士生。