东天山地区伊吾断裂晚第四纪活动特征  

LATE QUATERNARY ACTIVITY CHARACTERISTICS OF YIWU FAULT IN EAST TIANSHAN

作　　者：马建 陈建波[1] 赵纯青[1] 刘志坚[1] MA Jian;CHEN Jian-bo;ZHAO Chun-Qin;LIU Zhi-jian(Earthquake Agency of Xinjiang Autonomous Region,Urumqi 830011,Xinjiang,China)

机构地区：[1]新疆维吾尔自治区地震局,新疆乌鲁木齐830011

出　　处：《内陆地震》2021年第1期87-92,共6页Inland Earthquake

基　　金：地震应急青年重点任务(CEAEDEM201917);新疆地震科学基金(201911).

摘　　要：通过对伊吾断裂的实地调查,发现断裂在伊吾县城北侧的山前地带断错了晚第四纪洪积扇、T 3河流阶地,在地表形清晰的陡坎地貌,T 1阶地未见明显错动。依据探槽及天然露头揭露的剖面,认为研究区内断裂的运动方式以高角度逆冲为主。实测洪积扇上陡坎的高度在5~13 m区间内,T 3阶地的垂直高差达26 m,光释光测年结果表明研究区内T 3阶地的年龄为71~108 ka,初步估计伊吾断裂晚第四纪以来的垂直活动速率为0.24~0.37 mm/a。Based on the field investigation of Yiwu fault,it is found that the fault is located in the piedmont of the north side of Yiwu County,where the late Quaternary alluvial fan and T 3 river terrace are faulted.In the clear scarp landform on the surface,there is no obvious dislocation on T 1 terrace.According to the profile revealed by the trench and natural outcrop,it is considered that the movement mode of the faults in the study area is mainly high angle thrust.The measured height of scarp on the alluvial fan is in the range of 5~13 m,and the vertical height difference of T 3 terrace is 26 m.The results of optical luminescence dating show that the age of T 3 terrace in the study area is 71~108 ka,and it is estimated that the vertical activity rate of Yiwu fault since Late Quaternary is 0.24~0.37 mm/a.

关 键 词：伊吾断裂 晚第四纪 垂直位错 活动速率 

分 类 号：P315.9[天文地球—地震学]