The northern piedmont fault of Wutai Mountain is located at the north of the Shanxi Graben system, which is the dominating fault of the south boundary of the Fanshi-Daixian depression. This paper discusses the fault a...The northern piedmont fault of Wutai Mountain is located at the north of the Shanxi Graben system, which is the dominating fault of the south boundary of the Fanshi-Daixian depression. This paper discusses the fault activity and paleoearthquakes around the Nanyukou segment of the northern piedmont fault of Wutai Mountain during the late Quaternary through field investigation along the fault, measuring geomorphic deformation and excavating trenches at some important sites. From Nanyukou to the southwest of Shanhui, we find obviously dislocated alluvial fans, with strong neotectonic movement at these sites. Since nearly 20ka, the vertical average slip rate is 1.55mm/a to 2.0mm/a. However,since nearly 6ka,it has reached as high as 2.3mm/a, which is twice that on other segments. 2 trenches were excavated around Nanyukou with 6 events discovered. The referenced ages of the events are before 7600a, 6700a - 7600a, 5321a - 5575a, 4400a - 5400a,420Oa-4400a and after 1600a B.P. with approximate recurrence interval 1400a. The latest event is likely to be the earthquake occurring at 512 A. D. ,so it is necessary to do further work to verify this in the future.展开更多
基金sponsored by the specific fund for basic research and industry of Institute of Crustal Dynamics,China Earthquake administration ( ZDJ2008-07,ZDJ2007-14)co-financed by the Joint Earthquake foundation ( C07028)research and special fund for theseismic industry (200,708,028)
文摘The northern piedmont fault of Wutai Mountain is located at the north of the Shanxi Graben system, which is the dominating fault of the south boundary of the Fanshi-Daixian depression. This paper discusses the fault activity and paleoearthquakes around the Nanyukou segment of the northern piedmont fault of Wutai Mountain during the late Quaternary through field investigation along the fault, measuring geomorphic deformation and excavating trenches at some important sites. From Nanyukou to the southwest of Shanhui, we find obviously dislocated alluvial fans, with strong neotectonic movement at these sites. Since nearly 20ka, the vertical average slip rate is 1.55mm/a to 2.0mm/a. However,since nearly 6ka,it has reached as high as 2.3mm/a, which is twice that on other segments. 2 trenches were excavated around Nanyukou with 6 events discovered. The referenced ages of the events are before 7600a, 6700a - 7600a, 5321a - 5575a, 4400a - 5400a,420Oa-4400a and after 1600a B.P. with approximate recurrence interval 1400a. The latest event is likely to be the earthquake occurring at 512 A. D. ,so it is necessary to do further work to verify this in the future.
