关键词: 断裂带, 地震构造, 张家口-蓬莱构造带

Abstract: The Zhangjiakou penglai Northwest trending fault zone is an important seismotectonic zone in North China.We have done a preliminary study about its seismotectonic characters on the basis of the geological,geophsical and seismic activity data.The fault zone,which consists of nearly 20 NW-NWW trending faults,is a crust structure one which has an important controlling effect on the regional teconics of the Cenozoic Era.The fault zone is left lateral slip on the whole.In the Palaeogene period the zone's middle part was very active,after that its northwest and southeast sections became active in the Neogene period.The fault zone merges with several NE trending active teconic zone,so it owns a kind of tectonic combination that NW and NE trending faults intersect each other and includes 5 complex tectonic merging parts.The major earthquakes of M≥6 and most of middle small earthquakes assemble these parts.Both NW and NE trending fualts can cause earthquakes.So it demonstrates the character of conjugate ruptures.But the NE trending fault can produce bigger earthquakes than those of NW trending fault.The Zhangbei Shangyi 6.2 earthquake can be the result of northwestward extending along this fault zone.

Key words: Fault zone, Seismotectonics, ZhangjiakouPenglai tectonic belt