摘要
We have collected GPS data in the period of 1999-2007 from the Crustal Motion Observation Network of China along the Zhangjiakou-Bohai fault and its adjacent regions to study the characteristics of present-day crustal horizontal motion velocities in the research zone.Strain rate components are computed in the spheric coordinate system by the least square collocation method.According to the spatial distribution of the principal strain rate,dilation rate and maximum shear strain rate derived from GPS measurements,this paper analyses the deformation of the subordinary faults of the Zhangjiakou-Bohai fault.The principal compression strain rates are apparently greater than the principal extension strain rates.The larger shear strain rate is mainly in and around the Xianghe,Wenan and Tangshan areas in Hebei Province.According to the profiles across different segments of the Zhangjiakou-Bohai fault,the three segments glong the Zhangjiakou-Bohai fault show an obviously left-lateal strike-slip and compression characteristics.By analysis of the motion characteristics of the blocks,e.g.the Yanshan block,North China Plain block,Ordos block,and Ludong-Huanghai block in and around the North China region,this paper speculates that the dynamics of the motion styles of Zhangjiakou-Bohai fault may directly come from the relative movement between the Yanshan block and the North China plain block,and the ultimate dynamics may be the results of the collison between Indian plate and Eurasian plate,and the persistent northeastward extrusion of the Indian plate.
We have collected GPS data in the period of 1999-2007 from the Crustal Motion Observation Network of China along the Zhangjiakou-Bohai fault and its adjacent regions to study the characteristics of present-day crustal horizontal motion velocities in the research zone. Strain rate components are computed in the spheric coordinate system by the least square collocation method. According to the spatial distribution of the principal strain rate, dilation rate and maximum shear strain rate derived from GPS measurements, this paper analyses the deformation of the subordinary faults of the Zhangjiakou-Bohai fault. The principal compression strain rates are apparently greater than the principal extension strain rates. The larger shear strain rate is mainly in and around the Xianghe, Wen＇an and Tangshan areas in Hebei Province. According to the profiles across different segments of the Zhangjiakou-Bohai fault, the three segments glong the Zhangjiakou-Bohai fault show an obviously left-lateal strike-slip and compression characteristics. By analysis of the motion characteristics of the blocks, e.g. the Yanshan block, North China Plain block, Ordos block, and Ludong-Huanghai block in and around the North China region, this paper speculates that the dynamics of the motion styles of Zhangjiakou-Bohai fault may directly come from the relative movement between the Yanshan block and the North China plain block, and the ultimate dynamics may be the results of the collison between Indian plate and Eurasian plate, and the persistent northeastward extrusion of the Indian plate.
基金
funded by the Technology and Innovation Foundation of the First Monitoring Center of China Earthquake Administration (FMC2014018)
Science for Earthquake Resilience Project of China Earthquake Administration (XH15062)
National Natural Science Foundation Item of China (41372215
41272233)
