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.