中条山北麓断裂中南段全新世地震事件的初步研究  

HOLOCENE PALEOSEISMOLOGY OF THE MIDDLE AND SOUTH SEGMENTS OF THE NORTH ZHONGTIAOSHAN FAULT ZONE,SHANXI

作　　者：王怡然[1] 李有利[1] 闫冬冬[1] 吕胜华[1] 司苏沛[1] 

机构地区：[1]北京大学城市与环境学院地表过程重点实验室,北京100871

出　　处：《地震地质》2015年第1期1-12,共12页Seismology and Geology

基　　金：国家自然科学基金(41271019);中国地震局地震行业科研专项(200908001)共同资助

摘　　要：通过对中条山北麓断裂进行探槽研究,揭露了全新世以来,断裂中段和南段的3次古地震事件,包括1次发生在8 570-8 010a BP、贯通断裂中段和南段的8级以上特大地震,以及4 800-6 010a BP和2 110-320a BP发生的2次7级左右的大地震,地震复发间隔约为3 500a。研究表明,中条山北麓断裂的南段和中段在全新世发生过多次活动,活动性较强。Shanxi Graben System（ SGS） is a NNE-trending tectonic system located in the eastern and southern edges of Ordos Block and between Yinshan tectonic zone and Qinling tectonic zone.Composited with a series of NNE-,NE-trending graben basins,SGS is an important seismic zone in North China. Yuncheng Basin locates in the southern end of SGS,and is the deepest basin of the system. It is a half-graben with a shallow northern part and a deep southern part. As the south and east boundary of Yuncheng Basin,the North Zhongtiaoshan Fault Zone（ NZFZ） played a key role in the development of the topology and tectonics setting of Yuncheng Basin. NZFZ is a normal fault zone,NE-to NEE-trending and 130 km long. This fault zone can be divided into 3 segments： the south,the middle,and the north segment,and there are no historical M≥7,but only 3 M = 6 have taken place. Previous study suggests that the tectonic activity in this area is low and the earthquake interval is relatively long; seismic activity in the north and south segments is the weakest： the earthquake recurrence interval in the north segment is〉 50ka and it has not been active for 〉50ka,the interval of the south segment is - 12 ka and its last movement is about 7ka ago. Our work tells a different story： based on thorough fieldwork,satellite imagery analysis,and trench investigation,we found that there have been multiple earthquake events taking place in all of the 3 segments during Holocene. This study includes two trenches that locate in the south and middle segments of NZFZ,each of them renders 3 paleo-earthquake events： a 10 570 - 8 010 a BP event, an around 6670 - 6 550 a BP event,and a 2 110 - 320 a BP event in TC-1; a 7 930 - 11 300 a BP event,a4 800 - 6 010 a BP event,and a 2 680 a BP event in TC-2. Through comparing these events with other 2 trenches in the middle segment of NZFZ（ a XTC trench that renders a 19 980 a BP event and a 8 570 - 7 780 a BP event with 〉2. 2m vertical displacement; a XLC trench that renders a8 980 - 7 340 a BP even

关 键 词：中条山北麓断裂 古地震 探槽研究 活动断层 全新世 

分 类 号：P315.2[天文地球—地震学]