灵武断裂晚第四纪活动特征及位移速率

The Active Features and Slip Rate of Lingwu Faults in Late Quaternary

灵武断裂是银川地堑南段的东侧构造边界 ,与灵武—吴忠地区的地震活动有密切的关系 ,以往研究程度较低。作者通过实际调查、探槽开挖、年代侧定、相关地貌年代测定、断错历史研究等方面的大量工作对该断层晚第四纪的活动性开展了比较系统的野外考察。本文以野外考察获得的资料为基础 ,论述了该断层晚第四纪的活动特征 ,估计了其垂直位移速率。

The Lingwu fault is the east side structure boundary of the south section of Yinchuan graben.In this paper,on the basis of the data obtained from the field investigation,the late Quaternary active features and vertical displacements and its slip rates have been discussed.The fault is 48km in length,being divided into 3 segments according to geological and topographical features.The last rupture of the north and middle segments of the fault is during late Pleistocene and early Holocene and the south segment during middle Holocene.And the rupture has segmental property.The vertical slip rate is estimated as 0 23～0 25mm/a since about 66ka by vertical displacements of Ⅰ,Ⅱ and Ⅲ terraces and their ages.