摘要
冬青顶断裂段位于甘肃古浪皇城—双塔断裂的东段 ,由南北两条向北东方向呈弧形突出的近于平行的断裂组成。北断裂为挤压特征的逆冲断层 ,全长约 4 0km ,南断裂为具张性特征的正断层 ,全长约 34km ,二者具有内在的成生联系。该断裂全新世以来有过明显的构造活动。通过沿断裂带的追踪考察 ,在冬青顶断裂段上 ,开挖了 3个大型探槽 ,经综合对比发现该断裂近 15 0 0 0a以来共发生过 3次古地震事件和 1次历史地震事件 ,其发生年代分别是 :事件Ⅰ 15 930± 116 0aB P ,事件Ⅱ 94 6 0± 70 0aB P ,事件Ⅲ 5 0 0 0± 5 0 0aB P ,事件Ⅳ应是 192 7年古浪 8级大地震 (为历史地震事件 )。这
Dongqingding segment lies in the east part of Huangcheng-Shuangta active fault at Gulang County in Gangsu Province. It is consisted of two nearly-paralleled arch faults which protrude in northeast direction. One fault lies in the north and another fault lies in the south. The north fault is a compressional thrust fault that is about 40km long and the south one is a tensional normal fault that is about 34km long. Since Holocene, there have been obvious constructive activities on the fault. Based on forerunners'researches and the recent field investigation, three trenches have been dug on two chosen sites of the fault. The contrast results reveal that three palaeo-earthquakes and one historical-earthquake had occurred on the fault in the past 15,000 years. The age of the first earthquake is 15,930±1,160 years. The age of the second earthquake is 9,460±700 years. The age of the third earthquake is 5,000±500 years. The fourth earthquake must be the Gulang Ms 8.0 Earthquake which occurred in 1927. The four seismic events are obviously the approximate recurrent events with regard to the spatio-temporal distribution.
出处
《地震研究》
CSCD
北大核心
2004年第1期66-73,共8页
Journal of Seismological Research
基金
中国地震局地震科学联合基金项目 ( 10 2 0 5 5
60 40 18)资助
关键词
活动断裂
古地震
活动规律
皇城-双塔断裂
active fault, Palaeo-earthquake, seismicity, Huangcheng-Shuangta Fault
