郯庐断裂带安丘-莒县断裂江苏段全新世活动的新证据
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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,也是1668年郯城M8 1/2地震的发震断层。前人对郯城地震的地表破裂向S终止的位置存在多种观点,对该断裂江苏段的全新世活动情况也存在较大争议。文中通过在重岗山西侧和宿迁合欢路北侧开展的探槽开挖工作,发现了该断裂全新世活动的新证据,并对其最新活动时间进行了探讨。重岗山西侧后陈村探槽和宿迁合欢路北侧探槽都表明安丘-莒县断裂江苏段在全新世有过明显活动,推测最新一次古地震事件的发生时间为(4. 853±0. 012)～(2. 92±0. 3) ka BP。最新活动性质以走滑逆冲为主,剖面上获得的最大断错量为1m。未发现1668年郯城M81/2地震的地表破裂带到达江苏段的明确证据。
Anqiu-Juxian Fault is an important fault in the Tanlu fault zone,with the largest seismic risk,the most recent activity date and the most obvious surface traces. It is also the seismogenic fault of the Tancheng M8 1/2 earthquake in 1668. There are many different views about the southern termination location of surface rupture of the Tancheng earthquake and the Holocene activity in Jiangsu segment of this fault. Research on the latest activity time of the Jiangsu segment of Anqiu-Juxian Fault,particularly the termination location of surface rupture of the Tancheng earthquake,is of great significance to the assessment of its earthquake potential and seismic risk.Based on trench excavation on the Jiangsu segment of Anqiu-Juxian Fault,we discuss the time and characteristics of its latest activity. Multiple geological sections from southern Maling Mountain to Chonggang Mountain indicate that there was an ancient seismic event occurring in Holocene on the Jiangsu segment of Anqiu-Juxian Fault. We suggest the time of the latest seismic event is about( 4. 853±0. 012) ～( 2. 92±0. 3) ka BP by dating results. The latest activity is characterized by thrust strike-slip faulting, with the maximum displacement of 1 m. Combined with the fault rupture characteristics of each section,it is inferred that only one large-scale paleo-earthquake event occurred on the Jiangsu segment of Anqiu-Juxian Fault since the Holocene.The upper parts of the fault are covered by horizontal sand layers,not only on the trench in the west of Chonggang mountain but also on the trench in Hehuan Road in Suqian city,which indicates that the main part of the Jiangsu segment of Anqiu-Juxian Fault was probably not the surface rupture zone of the 1668 Tancheng M8 1/2 earthquake.In short,the Jiangsu segment of Anqiu-Juxian Fault has experienced many paleo-earthquake events since the late Pleistocene,with obvious activity during the Holocene. The seismic activities of the Jiangsu segment of Anqiu-Juxian Fault have the characteristics of large magnitude and low frequency. The Jiangsu segment of Anqiu-Juxian Fault has the deep tectonic and seismic-geological backgrounds of big earthquakes generation and should be highly valued by scientists.
Anqiu-Juxian Fault is an important fault in the Tanlu fault zone,with the largest seismic risk,the most recent activity date and the most obvious surface traces. It is also the seismogenic fault of the Tancheng M8 1/2 earthquake in 1668. There are many different views about the southern termination location of surface rupture of the Tancheng earthquake and the Holocene activity in Jiangsu segment of this fault. Research on the latest activity time of the Jiangsu segment of Anqiu-Juxian Fault,particularly the termination location of surface rupture of the Tancheng earthquake,is of great significance to the assessment of its earthquake potential and seismic risk.Based on trench excavation on the Jiangsu segment of Anqiu-Juxian Fault,we discuss the time and characteristics of its latest activity. Multiple geological sections from southern Maling Mountain to Chonggang Mountain indicate that there was an ancient seismic event occurring in Holocene on the Jiangsu segment of Anqiu-Juxian Fault. We suggest the time of the latest seismic event is about( 4. 853±0. 012) ～( 2. 92±0. 3) ka BP by dating results. The latest activity is characterized by thrust strike-slip faulting, with the maximum displacement of 1 m. Combined with the fault rupture characteristics of each section,it is inferred that only one large-scale paleo-earthquake event occurred on the Jiangsu segment of Anqiu-Juxian Fault since the Holocene.The upper parts of the fault are covered by horizontal sand layers,not only on the trench in the west of Chonggang mountain but also on the trench in Hehuan Road in Suqian city,which indicates that the main part of the Jiangsu segment of Anqiu-Juxian Fault was probably not the surface rupture zone of the 1668 Tancheng M8 1/2 earthquake.In short,the Jiangsu segment of Anqiu-Juxian Fault has experienced many paleo-earthquake events since the late Pleistocene,with obvious activity during the Holocene. The seismic activities of the Jiangsu segment of Anqiu-Juxian Fault have the characteristics of large magnitude and low frequency. The Jiangsu segment of Anqiu-Juxian Fault has the deep tectonic and seismic-geological backgrounds of big earthquakes generation and should be highly valued by scientists.
引文
曹筠,冉勇康,许汉刚,等.2015.宿迁城市活动断层探测多方法技术运用的典型案例[J].地震地质,37(2):430-439.doi:10.3969/j.issn.0253-4967.2015.02.007.CAO Jun,RAN Yong-kang,XU Han-gang,et al.2015.Typical case analysis on multi-method detection technology for active fault exploration in Suqian City[J].Seismology and Geology,37(2):430-439(in Chinese).
晁洪太,李家灵,崔昭文,等.1994.郯庐断裂带中段全新世活断层的几何结构与分段[G]∥邓起东.活动断裂研究(3).北京:地震出版社.180-190.CHAO Hong-tai,LI Jia-ling,CUI Zhao-wen,et al.1994.Geometry and segmentation of the Holocene fault in the central section of the Tanlu fault zone[G]∥Deng Qi-dong.Research on Active Fault in China(3).Seismological Press,Beijing:180-l90(in Chinese).
晁洪太,李家灵,崔昭文,等.1997.郯庐断裂带潍坊-嘉山段全新世活断层的活动方式与发震模式[J].地震研究,20(4):218-226.CHAO Hong-tai,LI Jia-ling,CUI Zhao-wen,et al.1997.Mode of motion of the Holocene fault zone in WeifangJiashan segment of the Tanlu fault zone and earthquake-generating model[J].Journal of Seismological Research,20(4):218-226(in Chinese).
方仲景,丁梦林,向宏发,等.1987.郯庐断裂[M].北京:地震出版社.FANG Zhong-jing,DING Meng-lin,XIANG Hong-fa,et al.1987.The Tanlu Fault Zone[M].Seismological Press,Beijing(in Chinese).
高维明,郑朗荪,李家灵,等.1988.1668年山东郯城8.5级地震的发震构造[J].中国地震,4(3):9-15.GAO Wei-ming,ZHENG Lang-sun,LI Jia-ling,et al.1988.Seismogenic fault of the 1668 Tancheng earthquake(M=8.5)[J].Earthquake Research in China,4(3):9-15(in Chinese).
李家灵,晁洪太,崔昭文,等.1991.郯庐断裂带郯城-新沂段活断层研究[G]∥邓起东.活动断裂研究(1)[M].北京:地震出版社.LI Jia-ling,CHAO Hong-tai,CUI Zhao-wen,et al.1991.Research on the active fault in Tancheng-Xinyi segment of Tanlu fault zone[G]∥Deng Qi-dong.Research on Active Fault in China(1).Seismological Press,Beijing(in Chinese).
李家灵,晁洪太,崔昭文,等.1994.1668年郯城8.5级地震断层及其破裂机制[J].地震地质,16(3):229-237.LI Jia-ling,CHAO Hong-tai,CUI Zhao-wen,et al.1994.Seismic fault of the 1668 Tancheng earthquake(M=8.5)and its fracture mechanism[J].Seismology and Geology,16(3):229-237(in Chinese).
李起彤.1994.郯庐断裂带江苏段全新世活动新证据[G]∥邓起东.中国活动断层研究.北京:地震出版社.LI Qi-tong.1994.New evidence for the Holocene movement along the Jiangsu segment of the Tanlu fault zone[G]∥Deng Qi-dong.Research on Active Fault in China.Seismological Press,Beijing(in Chinese).
冉勇康,王虎,杨会丽,等.2014.中国大陆古地震研究的关键技术与案例解析(4):古地震定年技术的样品采集和事件年代分析[J].地震地质,36(4):939-955.doi:0.3969/j.issn.0253-4967.2014.04.001.RAN Yong-kang,WANG Hu,YANG Hui-li,et al.2014.Key techniques and several cases analysis in paleoseismic studies in mainland China(4):Sampling and event analysis of paleoseismic dating methods[J].Seismology and Geology,36(4):939-955.
沈小七,姚大全,郑海刚,等.2015.郯庐断裂带重岗山-王迁段晚更新世以来的活动习性[J].地震地质,37(1):139-148.doi:10.3969/j.issn.0253-4967.2015.11.SHEN Xiao-qi,YAO Da-quan,ZHENG Hai-gang,et al.2015.The research on active behavior of ChonggangshanWangqian segment of Tanlu fault zone since Pleistocene[J].Seismology and Geology,37(1):139-148(in Chinese).
王华林.1995.1668年郯城8.5级地震的全新世滑动速率、古地震和强震复发周期[J].西北地震学报,17(4):1-12.WANG Hua-lin.1995.Holocene displacement rate,paleoearthquakes and recurrence intervals of strong earthquake along the 1668 Tancheng earthquake(MS=8.5)fault[J].Northwestern Seismological Journal,17(4):1-12(in Chinese).
谢瑞征,朱书俊,丁政.1991.郯庐断裂带江苏段全新世活动问题的商榷[J].地震学刊,(4):15-17.XIE Rui-zheng,ZHU Shu-jun,DING Zheng.1991.Discuss on activity in Holocene of the Jiangsu segment of the Tanlu fault zone[J].Journal of Seismology,(4):15-17(in Chinese).
许汉刚,范小平,冉勇康,等.2016.郯庐断裂带宿迁段F5断裂浅层地震勘探新证据[J].地震地质,38(1):31-43.doi:10.3969/j.issn.0253-4967.2016.01.003.XU Han-gang,FAN Xiao-ping,RAN Yong-kang,et al.2016.New evidences of the Holocene fault in Suqian segment of the Tanlu fault zone discovered by shallow seismic exploration method[J].Seismology and Geology,38(1):31-43(in Chinese).
杨源源,赵朋,郑海刚,等.2017.郯庐断裂带安徽紫阳山段发现全新世活动证据[J].地震地质,39(4):644-655.doi:10.3969/j.issn.0253-4967.2017.04.002.YANG Yuan-yuan,ZHAO Peng,ZHENG Hai-gang,et al.2017.Evidence of Holocene activity discovered in Anhui Ziyangshan segment of Tanlu fault zone[J].Seismology and Geology,39(4):644-655(in Chinese).
杨源源,郑海刚,姚大全,等.2016.郯庐断裂带中段嶂山断裂东侧断裂活动特征[J].地震地质,38(3):582-595.doi:10.3969/j.issn.0253-4967.2016.03.006.YANG Yuan-yuan,ZHENG Hai-gang,YAO Da-quan,et al.2016.Active features of faults at the east of Zhangshan on the middle segment of Tanlu fault zone[J].Seismology and Geology,38(3):582-595(in Chinese).
张鹏,李丽梅,冉勇康,等.2015.郯庐断裂带安丘-莒县断裂江苏段晚第四纪活动特征研究[J].地震地质,37(4):1162-1176.doi:10.3969/j.issn.0253-4967.2015.04.018.ZHANG Peng,LI Li-mei,RAN Yong-kang,et al.2015.Research on characteristics of late Quaternary activity of the Jiangsu segment of Anqiu-Juxian Fault in the Tanlu fault zone[J].Seismology and Geology,37(4):1162-1176(in Chinese).
Liu B,Zhu G,Zhai M J,et al.2015.Quaternary faulting of the Jiangsu part of the Tanlu fault zone,East China:Evidence from field investigations and OSL dating[J].Journal of Asian Earth Science,114:89-102.
Min W,Liu Y G,Jiao D C,et al.2013.Evidence for Holocene activity of the Yilan-Yitong Fault,northeastern of the Tanlu fault zone in Northeast China[J].Journal of Asian Earth Science,67-68:207-216.
(1)江苏省地质局,1980,宿迁幅区域水文地质普查报告。
(1)中国地震局地质研究所,江苏省地震工程研究院,2015,宿迁市活动断层宿迁市活动断层探测与地震危险性评价项目目标断层的晚第四纪活动性鉴定报告。
晁洪太,李家灵,崔昭文,等.1994.郯庐断裂带中段全新世活断层的几何结构与分段[G]∥邓起东.活动断裂研究(3).北京:地震出版社.180-190.CHAO Hong-tai,LI Jia-ling,CUI Zhao-wen,et al.1994.Geometry and segmentation of the Holocene fault in the central section of the Tanlu fault zone[G]∥Deng Qi-dong.Research on Active Fault in China(3).Seismological Press,Beijing:180-l90(in Chinese).
晁洪太,李家灵,崔昭文,等.1997.郯庐断裂带潍坊-嘉山段全新世活断层的活动方式与发震模式[J].地震研究,20(4):218-226.CHAO Hong-tai,LI Jia-ling,CUI Zhao-wen,et al.1997.Mode of motion of the Holocene fault zone in WeifangJiashan segment of the Tanlu fault zone and earthquake-generating model[J].Journal of Seismological Research,20(4):218-226(in Chinese).
方仲景,丁梦林,向宏发,等.1987.郯庐断裂[M].北京:地震出版社.FANG Zhong-jing,DING Meng-lin,XIANG Hong-fa,et al.1987.The Tanlu Fault Zone[M].Seismological Press,Beijing(in Chinese).
高维明,郑朗荪,李家灵,等.1988.1668年山东郯城8.5级地震的发震构造[J].中国地震,4(3):9-15.GAO Wei-ming,ZHENG Lang-sun,LI Jia-ling,et al.1988.Seismogenic fault of the 1668 Tancheng earthquake(M=8.5)[J].Earthquake Research in China,4(3):9-15(in Chinese).
李家灵,晁洪太,崔昭文,等.1991.郯庐断裂带郯城-新沂段活断层研究[G]∥邓起东.活动断裂研究(1)[M].北京:地震出版社.LI Jia-ling,CHAO Hong-tai,CUI Zhao-wen,et al.1991.Research on the active fault in Tancheng-Xinyi segment of Tanlu fault zone[G]∥Deng Qi-dong.Research on Active Fault in China(1).Seismological Press,Beijing(in Chinese).
李家灵,晁洪太,崔昭文,等.1994.1668年郯城8.5级地震断层及其破裂机制[J].地震地质,16(3):229-237.LI Jia-ling,CHAO Hong-tai,CUI Zhao-wen,et al.1994.Seismic fault of the 1668 Tancheng earthquake(M=8.5)and its fracture mechanism[J].Seismology and Geology,16(3):229-237(in Chinese).
李起彤.1994.郯庐断裂带江苏段全新世活动新证据[G]∥邓起东.中国活动断层研究.北京:地震出版社.LI Qi-tong.1994.New evidence for the Holocene movement along the Jiangsu segment of the Tanlu fault zone[G]∥Deng Qi-dong.Research on Active Fault in China.Seismological Press,Beijing(in Chinese).
冉勇康,王虎,杨会丽,等.2014.中国大陆古地震研究的关键技术与案例解析(4):古地震定年技术的样品采集和事件年代分析[J].地震地质,36(4):939-955.doi:0.3969/j.issn.0253-4967.2014.04.001.RAN Yong-kang,WANG Hu,YANG Hui-li,et al.2014.Key techniques and several cases analysis in paleoseismic studies in mainland China(4):Sampling and event analysis of paleoseismic dating methods[J].Seismology and Geology,36(4):939-955.
沈小七,姚大全,郑海刚,等.2015.郯庐断裂带重岗山-王迁段晚更新世以来的活动习性[J].地震地质,37(1):139-148.doi:10.3969/j.issn.0253-4967.2015.11.SHEN Xiao-qi,YAO Da-quan,ZHENG Hai-gang,et al.2015.The research on active behavior of ChonggangshanWangqian segment of Tanlu fault zone since Pleistocene[J].Seismology and Geology,37(1):139-148(in Chinese).
王华林.1995.1668年郯城8.5级地震的全新世滑动速率、古地震和强震复发周期[J].西北地震学报,17(4):1-12.WANG Hua-lin.1995.Holocene displacement rate,paleoearthquakes and recurrence intervals of strong earthquake along the 1668 Tancheng earthquake(MS=8.5)fault[J].Northwestern Seismological Journal,17(4):1-12(in Chinese).
谢瑞征,朱书俊,丁政.1991.郯庐断裂带江苏段全新世活动问题的商榷[J].地震学刊,(4):15-17.XIE Rui-zheng,ZHU Shu-jun,DING Zheng.1991.Discuss on activity in Holocene of the Jiangsu segment of the Tanlu fault zone[J].Journal of Seismology,(4):15-17(in Chinese).
许汉刚,范小平,冉勇康,等.2016.郯庐断裂带宿迁段F5断裂浅层地震勘探新证据[J].地震地质,38(1):31-43.doi:10.3969/j.issn.0253-4967.2016.01.003.XU Han-gang,FAN Xiao-ping,RAN Yong-kang,et al.2016.New evidences of the Holocene fault in Suqian segment of the Tanlu fault zone discovered by shallow seismic exploration method[J].Seismology and Geology,38(1):31-43(in Chinese).
杨源源,赵朋,郑海刚,等.2017.郯庐断裂带安徽紫阳山段发现全新世活动证据[J].地震地质,39(4):644-655.doi:10.3969/j.issn.0253-4967.2017.04.002.YANG Yuan-yuan,ZHAO Peng,ZHENG Hai-gang,et al.2017.Evidence of Holocene activity discovered in Anhui Ziyangshan segment of Tanlu fault zone[J].Seismology and Geology,39(4):644-655(in Chinese).
杨源源,郑海刚,姚大全,等.2016.郯庐断裂带中段嶂山断裂东侧断裂活动特征[J].地震地质,38(3):582-595.doi:10.3969/j.issn.0253-4967.2016.03.006.YANG Yuan-yuan,ZHENG Hai-gang,YAO Da-quan,et al.2016.Active features of faults at the east of Zhangshan on the middle segment of Tanlu fault zone[J].Seismology and Geology,38(3):582-595(in Chinese).
张鹏,李丽梅,冉勇康,等.2015.郯庐断裂带安丘-莒县断裂江苏段晚第四纪活动特征研究[J].地震地质,37(4):1162-1176.doi:10.3969/j.issn.0253-4967.2015.04.018.ZHANG Peng,LI Li-mei,RAN Yong-kang,et al.2015.Research on characteristics of late Quaternary activity of the Jiangsu segment of Anqiu-Juxian Fault in the Tanlu fault zone[J].Seismology and Geology,37(4):1162-1176(in Chinese).
Liu B,Zhu G,Zhai M J,et al.2015.Quaternary faulting of the Jiangsu part of the Tanlu fault zone,East China:Evidence from field investigations and OSL dating[J].Journal of Asian Earth Science,114:89-102.
Min W,Liu Y G,Jiao D C,et al.2013.Evidence for Holocene activity of the Yilan-Yitong Fault,northeastern of the Tanlu fault zone in Northeast China[J].Journal of Asian Earth Science,67-68:207-216.
(1)江苏省地质局,1980,宿迁幅区域水文地质普查报告。
(1)中国地震局地质研究所,江苏省地震工程研究院,2015,宿迁市活动断层宿迁市活动断层探测与地震危险性评价项目目标断层的晚第四纪活动性鉴定报告。