SEISMOLOGY AND GEOLOGY ›› 2016, Vol. 38 ›› Issue (3): 582-595.DOI: 10.3969/j.issn.0253-4967.2016.03.006

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ACTIVITY FEATURES OF FAULTS AT THE EAST OF ZHANGSHAN ON THE MIDDLE SEGMENT OF TANLU FAULT ZONE

YANG Yuan-yuan1, ZHENG Hai-gang1, YAO Da-quan1, SHU Peng1, ZHAO Peng1, SHENG Xiao-qi2   

  1. 1 Anhui Earthquake Administration, Heifei 230031, China;
    2 First Crust Monitoring and Application Center, China Earthquake Adiministration, Tianjin 300180, China
  • Received:2015-05-08 Revised:2016-07-28 Online:2016-09-20 Published:2016-10-15

郯庐断裂带中段嶂山东侧断裂的活动特征

杨源源1, 郑海刚1, 姚大全1, 疏鹏1, 赵朋1, 沈小七2   

  1. 1 安徽省地震局, 合肥 230031;
    2 中国地震局第一监测中心, 天津 300180
  • 通讯作者: 姚大全,男,研究员,E-mail:daquany@aheq.gov.cn
  • 作者简介:杨源源,男,1988年生,2013年于中国地震局地震预测研究所获硕士学位,研究方向为地震地质和地震综合分析预报,E-mail:yuanyuanyang_1988@126.com。
  • 基金资助:

    中国地震局地震行业科研专项(201308012)、安徽省公益性地质工作项目(2015025)与安徽省地震科研基金青年项目(20160605)共同资助

Abstract:

Given the scarcity of research on the activity of Xinyi-Sihong segment of the Tanlu Fault zone, this paper focuses on the Zhangshan segment where there are quite evident geomorphic features to complement the shortage of the research on the northern part of Xinyi-Sihong segment. This study enriches evidences for the late Quaternary activity and paleoseismological events on the Xinyi-Sihong segment. The Zhangshan segment is located at Xiaodian Town to Jintou Village of Suqian City, stretching towards NE for 7 kilometers with a dip angle of 60~80. Research of tectonic geomorphology shows that gullies in northern part of Zhangshan segment were evidently displaced, while in the southern, two NE-trending right-stepped fault scarps are developed, with an average height of 3 meters, which generally suggests that the fault was dominated by thrust and dextral motion. Two trenches were excavated in the southern part of Zhangshan segment, numbered Mayao trench 1 and Mayao trench 2. Both trenches reveal that:(1)within this segment, Tanlu Fault shows periodic fault activity, that is, normal faulting during Pliocene epoch while thrust faulting in Quaternary period; (2)an event occurred between 15.12ka BP to 11.82 BP; (3)the latest event possibly took place around 3 500 a BP. Based on integrated results of previous studies, we identify the dates of paleoseismic events on the Xinyi-Sihong segment as follows:more than 960 thousands years ago, early to middle period of late Pleistocene, (15.12~11.82)ka BP, (11.76±0.05)ka~(10.53±0.05)ka BP, (10.15±0.05)ka~(8.16±0.05)ka BP and 4 960~3 510a BP.

Key words: Tanlu Fault zone, paleoseismic events, Xinyi-Sihong segment, Zhangshan segment

摘要:

目前对于郯庐断裂带新沂-泗洪段的研究相对薄弱,通过对该段北侧构造地貌条件较好的嶂山段开展研究,充实了该段的晚第四纪活动证据与古地震事件序列。嶂山段总体位于宿迁市晓店镇至井头乡一带,长约7km。构造地貌研究显示嶂山段晚第四纪活动具有逆冲右旋的运动性质。古地震探槽研究揭示:1)郯庐断裂在该段具有分期活动特征,上新世期间为拉张正断,第四纪以来表现为逆冲;2)1次古地震发生在15.12~11.82ka BP;3)断裂最新活动年代可能为3 500a BP左右。综合前人的研究成果,目前郯庐断裂带新沂-泗洪段已揭露的古地震事件年代序列可归纳为:9.6×104a以前,晚更新世早、中期,15.12~11.82ka BP,(11.76±0.05)~(10.53±0.05) ka BP,(10.15±0.05)~(8.16±0.05) ka BP,4 960~3 510a BP。

关键词: 郯庐断裂带, 古地震, 新沂, 泗洪, 嶂山

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