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榆木山北缘断裂古地震特征研究
PALAEO-EARTHQUAKE STUDY ON THE NORTHERN YUMUSHAN ACTIVE FAULT
【摘要】 榆木山北缘断裂位于祁连山主体山系以北的榆木山北部边缘。断裂活动形成一系列沿山前发育的断层陡坎。通过探槽剖面对发生在该断裂带上的古地震事件进行了分析,大致可以确定全新世以来的2次古地震事件。事件Ⅰ的年代为距今(4.066±0.086)ka;事件Ⅱ为距今(6.852±0.102)ka至(6.107±0.082)ka之间。该断裂的最后一次古地震事件发生在距今(4.066±0.086)ka,并非公元180年表氏71/2级地震的发震断裂。
【Abstract】 The northern Yumushan Fault located on the northern flank of Qilian fold system is an active fault in Holocene.The fault is about 60km long,trending NWW.It is a trust fault with left-lateral strike-slip component.The activity of the fault produced a series of scarps along the mountain front.The fault zone is divided into three segments,and the middle part is the most active.In this paper,palaeo-earthquake events on the fault are studied.With the study of trench profiles,two palaeo-earthquake events are determined.Event I occurred at 4.066±0.086kaBP,and event II is between 6.852±0.102kaBP and 6.107±0.082ka BP.The last palaeo-earthquake event on this fault occurred in 4.066±0.086kaBP.So,the northern Yumushan Fault is not the seismogenic fault of the M 71/2 Biaoshi earthquake of 180 AD.The elapse time from the latest event has been 4000yr,so the possibility of generating destructive earthquake in future should be recognized sufficiently.
【Key words】 Northern Yumushan Fault; palaeo-earthquake; Hexi Corridor; the M 71/2 Biaoshi earthquake in 180 AD;
- 【文献出处】 地震地质 ,Seismology and Geology , 编辑部邮箱 ,2011年02期
- 【分类号】P315.2
- 【被引频次】10
- 【下载频次】114