华北地区活动地块边界带运动及块体内部变形分析

基于刚性块体和GPS稳定点组概念,用GPS稳定点组的水平速度值求出了各活动地块及华北亚板块的欧拉运动参数,推证了块体边界上的点相对运动速度矢量公式,通过该公式利用块体欧拉运动参数反演计算分析了地块边界带运动状况;通过块体欧拉运动参数反演计算各GPS观测点的背景运动速度,用观测点的实测运动速度减去各观测点的背景运动速度得出其实际变形值,进一步分析了各地块内部变形情况;并探讨了各活动地块的刚性特征。

Crustal Movement on the Boundary Zones Between Active Blocks and Internal Deformation of Blocks in North China

In this paper,we study the relative motion in the boundaries between blocks.We also invert the velocity for GPS monitoring station based on these Euler vectors,which act as the background velocity.Therefore,the deformation field in intra_block is obtained through observational velocity field reducing background velocity field.These deformation fields in intra_block are also used to study the rigidity for active blocks in North China.The GPS results show that: 1) Shanxi graben system is an active extension border with slight dextral rotation. 2) The center_southern segment of Taihang mountain front fault system is a compression border,the center_northern segment of Tanlu fault system is an active extension border ,but southern segment (Linyi Segment) is an active compressional border. 3) The Yinshan segment belonging to Yinshan_Yanshan active tectonic zones has slight extension activity,and is an active extension border with slight dextral rotation. 4) The internal deformation in Ordos block is rather small,which indicates that the medium in this block is better in rigidity.This result is consistent with that obtained geological analysis. 5) Except in boundaries between active blocks,the internal deformation in Beijing_Tianjin_Tangshan area is larger and disorder,and the deformation magnitude and direction of the sites such as H063,G0AG,G179,H069 are greatly different from those of other sites.These sites and areas should be monitored and studied further by GPS and other technologies.