基于GPS资料反演中国大陆主要断裂现今活动速率

GPS-constrained inversion of present-day slip rates along major faults in Chinese mainland

断层活动速率分布提供了中国大陆地壳运动变形的图像.它不仅是解释中国大陆岩石圈变形动力学原因的关键,还是评估未来地震危险性的关键参数之一.本文根据中国大陆活动构造和地震活动分布建立了三维弹性块体模型,并利用最新的GPS资料计算了作为一个整体的断层系统中自洽的断层活动速率.计算结果显示,中国大陆内部绝大多数断裂带的活动速率小于20mm/a,并不存在类似于板块边界的快速运动.另外,中国大陆断裂带的活动存在东西差异,东部断裂带的活动速率大多低于1.0mm/a,而西部断裂带的活动速率最高达到18mm/a.本文给出的断层长期活动速率结果为中国大陆现今运动变形的动力学研究提供了新的约束.

Distribution of fault slip rates shows the pattern of crustal movement and deformation. It is not only one of the key parameters to interprate the geodynamics of crustal deformation, but also one of the key parameters for assessing seismic hazard. A three-dimensional elastic block model in the Chinese continent is constructed based on studies of active tectonics and seismicity. Coherent fault slip rates in an integral fault system are constrained using updated GPS data. Inversion results show that slip rates along most major faults are less than 20 mm/a in the Chinese continent. The rapid fault activity like fault motion on the plate houndarics dones not exist in the China mainland. Motion styles of major faults in western China and in the eastern China are different. Slip rates on faults in the eastern China are mainly less than 1.0 mm/a, while the highest slip rate along faults in the western China reaches 20 mm/a. The fault slip rates constrained by our model provide a new constraint for the geodynamics of present-day crustal deformation in the Chinese mainland.