SEISMOLOGY AND GEOLOGY ›› 2015, Vol. 37 ›› Issue (4): 1162-1176.DOI: 10.3969/j.issn.0253-4967.2015.04.018

• Research Paper • Previous Articles     Next Articles

research on characteristics of late quaternary activity of the jiangsu segment of anqiu-juxian fault in the tanlu fault zone

ZHANG Peng1, LI Li-mei1, RAN Yong-kang2, CAO Jun2, XU Han-gang1, JIANG Xin1   

  1. 1. Earthquake Administration of Jiangsu Province, Nanjing 210014, China;
    2. Institute of Geology, China Earthquake Administration, Beijing 100085, China
  • Received:2015-02-03 Online:2015-12-20 Published:2016-01-28

郯庐断裂带安丘-莒县断裂江苏段晚第四纪活动特征研究

张鹏1, 李丽梅1, 冉勇康2, 曹筠2, 许汉刚1, 蒋新1   

  1. 1. 江苏省地震局, 南京 210014;
    2. 中国地震局地质研究所, 北京 100029
  • 作者简介:张鹏, 男, 1981年生, 2007年于南京大学地球科学系获构造地质学专业博士学位, 高级工程师,研究方向为构造地质与地震地质, E-mail:zhpnju@163.com。
  • 基金资助:

    国家自然科学基金(41202155)、宿迁市活动断层探测与地震危险性评价项目(SQZBTB20110162)与财政部专项“我国重点监视防御区活动断层地震危险性评价”(1521201100030)共同资助

Abstract:

Anqiu-Juxian Fault is an important fault in the Tanlu fault zone, with the highest seismic risk, the most recent activity date, and the most obvious surface traces. Due to lack of credible geological evidences, there is big controversy on the Holocene activity in the Jiangsu segment of this fault. Research on the characteristics of late Quaternary activity in the Jiangsu segment of Anqiu-Juxian Fault, particularly its latest activity time, is of great significance to assessment of its earthquake ability and seismic risk. Based on field investigations on the Jiangsu segment of Anqiu-Juxian Fault, and combining with the results of fault activities identification on this fault in Suqian City, we discussed the characteristics of its activities in late Quaternary. Multiple geological sections we found in this study and the results of fault activities identification in Suqian City all indicate that there was an ancient seismic event occurring in middle period of Holocene in the segment from southern Maling Mountain to Suqian City; but the trench at Houchen village did not show any evidence of Holocene activity on the Chonggangshan segment of this fault. Based on method of shallow seismic exploration, we carried out a systematic exploration of this fault to get its accurate position and activity characteristics. The results show that Anqiu-Juxian Fault in Suqian City is mainly characterized by dextral strike-slip, associated with both thrusting and extensional movement in different positions. A series of low hills were formed along the fault in the north of Suqian City, and a small graben basin was formed in the south of Suqian City, both are controlled by the dextral strike-slip movement of this fault. The Jiangsu segment of Anqiu-Juxian Fault in general is characterized by dextral strike-slip with thrusting movement. But some parts of it are characterized by dextral strike-slip with extensional movement. The Jiangsu segment of Anqiu-Juxian Fault experienced a number of activities since the late Quaternary, with an obvious activity in Holocene. The seismic activities of Jiangsu segment of Anqiu-Juxian Fault have the characteristic of high intensity and low frequency. Its activities decrease gradually from north to south as a whole.

Key words: the Tanlu fault zone, Anqiu-Juxian Fault, the Jiangsu segment, late Quaternary activity, field investigation

摘要:

安丘-莒县断裂是郯庐断裂带内活动时代最新、地表形迹最明显, 地震危险性最大的断裂。因缺少可信的地质证据, 前人对于该断裂江苏段的全新世活动情况存在较大争议。文中根据对郯庐断裂带安丘-莒县断裂江苏段开展的野外调查工作成果, 结合在宿迁市地区开展的断层活动性鉴定工作成果, 对该断裂的晚第四纪活动特征进行了探讨。本次发现的多个断裂剖面及宿迁地区的断层活动性鉴定成果都表明安丘-莒县断裂的南马陵山—宿迁段在全新世中期发生过1次古地震事件; 而后陈村探槽表明该断裂重岗山段无全新世活动迹象。安丘-莒县断裂江苏段晚第四纪活动总体以右旋走滑兼挤压逆冲为特征, 局部地区则以走滑正断为主。安丘-莒县断裂江苏段自晚更新世以来经历了多次活动, 在全新世也有明显活动, 其地震活动具强度大、频度低的特点, 其活动性总体自北向南逐渐减弱。

关键词: 郯庐断裂带, 安丘-莒县断裂, 江苏段, 晚第四纪活动性, 野外调查

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