SEISMOLOGY AND GEOLOGY ›› 2017, Vol. 39 ›› Issue (3): 550-560.DOI: 10.3969/j.issn.0253-4967.2017.03.008

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THE NEW ACTIVITY OF TAN-LU FAULT ZONE IN SEGMENT OF DAHONGSHAN SINCE LATE QUATERNARY

ZHAO Peng1,2, YAO Da-quan1,2, YANG Yuan-yuan1, ZHENG Hai-gang1, FANG Liang-hao1   

  1. 1 Anhui Earthquake Administration, Hefei 230031, China;
    2 Key Laboratory on the Study of Middle-Southern Segment of Tanlu Fault Zone, Anhui Earthquake Administration, Hefei 230031, China
  • Received:2015-07-27 Revised:2016-01-17 Online:2017-06-20 Published:2017-07-20

郯庐断裂带大红山段晚第四纪以来的新活动

赵朋1,2, 姚大全1,2, 杨源源1, 郑海刚1, 方良好1   

  1. 1 安徽省地震局, 合肥 230031;
    2 安徽省地震局, 郯庐断裂带中南段重点研究室, 合肥 230031
  • 通讯作者: 姚大全,男,研究员,E-mail:daquany@ah.eq.gov.cn
  • 作者简介:赵朋,男,1982年生,2009年在中国地震局地质研究所获硕士学位,工程师,研究方向为地震地质及地震中长期预测,电话:13635516032,E-mail:zp20031688@163.com。
  • 基金资助:
    安徽省公益性地质工作项目(2015-g-25)与地震科技星火计划青年项目(XH16018Y)共同资助

Abstract: The relationship between the latest activity of active fault and seismic events is of the utmost importance. The Tan-lu fault zone in eastern China is a major fault zone, of which the active characteristics of the segments in Jiangsu, Shandong and Anhui has been the focus of research. This study takes the Dahongshan segment of the Tanlu Fault in Sihong County as the main research area. We carried out a detailed geological survey and excavated two trenches across the steep slope on the southwest side of the Dahongshan. Each trench shows fault clearly. Combining the comparative analysis of previous work, we identified and cataloged the late Quaternary deformation events and prehistoric earthquake relics, and analyzed the activity stages and behavior of this segment.
Fault gonge observed in the trench profiles shows that multiple earthquake events occurred in the fault. The faulting dislocated the Neogene sandstone, black gravel layer and gray clay layer. Brown clay layer is not broken. According to the relations of dislocated stratums, corresponding 14C and OSL samples were collected and dated. The result indicates that the Dahongshan segment of the Tanlu Fault has experienced strong earthquakes since the late Quaternary. Thrust fault, normal fault and strike-slip fault are found in the trenches. The microscopic analysis of slices from fault shows that there are many stick-creep events taking place in the area during the late Quaternary. Comprehensive analysis shows that there have been many paleoearthquakes in this region since the late Quaternary, the recent active time is the late Pleistocene, and the most recent earthquake event occurred in(12~2.5ka BP).
The neotectonic activity is relatively weak in the Anhui segment(south of the Huaihe River)of Tanlu fault zone. There are difficulties in the study of late Quaternary activity. For example, uneven distribution of the Quaternary, complex geological structure, larger man-made transformation of surface and so on. The progressive research may be able to promote the study on the activity of the Anhui segment of Tanlu fault zone.

Key words: Tanlu fault zone, Dahongshan segment, late late Pleistocene, geological trench

摘要: 活动断裂的最新活动与地震事件的关系至关紧要。以郯庐断裂带苏皖交界处的泗洪县峰山乡大红山段开挖的探槽为主要研究对象,结合前人工作的对比分析,识别编录晚第四纪以来的变形现象,分析其活动习性。2个探槽剖面均揭示了明显的断层现象,显示断层错断了晚更新世含砾石黏土层,表现为张扭运动形式。结合地层年代样品测试结果,分析认为该断层段所在地区第四纪以来发生过多次地震活动,断层最新活动时代为晚更新世晚期,最近1次地震事件发生在12~2.5ka BP。

关键词: 郯庐断裂带, 大红山段, 晚更新世晚期, 地质探槽

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