Late Quaternary tectonic deformation and seismic risk assessment in the middle section of Nankou-Sunhe fault in Beijing plain
The Nankou-Sunhe fault is the largest and most influential NW-trending fault in Beijing plain.It is located in the Zhangjiakou-Bohai seismic and tectonic belt,with a length of about 80 km,and it is a left-lateral,strike-slip and normal fault.A M 6 earthquake occurred along the fault in 1536,a M 43/4 earthquake in 1664,a M 5 earthquake in 1746 and a M 4.5 earthquake in 1990.However,previous studies mainly focused on the northwestern and southeastern sections of the fault,which directly limited the understanding and evaluation of Late Quaternary tectonic deformation and seismic risk in the middle sections of the fault.Based on shallow seismic exploration,this paper reveals the shape,characteristics and distribution position of the middle section of the Nankou-Sunhe fault.The middle part of the fault tends to the NE,which is opposite to the NW part of the fault.The structural deformation of the middle section of the fault was strong since Late Quaternary,and the latest activity age was middle and late Late Pleistocene.According to the fitting relationship between magnitude and fault in North China,the potential strong earthquake risk of Nankou-Sunhe fault in the future is comprehensively evaluated.It is considered that there will be a potential strong earthquake risk of 7.0-8.0 magnitude earthquake in the future.In particular,the stress in the intersection area of the fault and the NE fault is easier to concentrate,which needs more attention.
万方数据
维普
