地表弱活动断裂6~7级地震中长期预测技术要点与案例解析
|
摘要
6~7级地震地表位错量往往很小甚至不断错地表,其发震断裂很容易被误判为非全新世活动断裂而导致其未来强震危险性被忽视。对此,文中特提出未来可能发生6~7级地震的地表弱活动断裂类型。甄别地表弱活动断裂是6~7级地震中长期预测技术的关键,技术要点是:在目标断裂所属构造系统的发震能力判定基础上,构建起目标断裂与同一构造背景中具历史地震记载或古地震地质记录的活动断裂之间的某种联系。实际案例解析结果表明,同一级次相似构造、同一构造系统不同孕震构造单元,以及特定构造过程中不同阶段构造级次的类比,是地表弱活动断裂6~7级地震中长期预测较为有效的技术方法。昆明市普渡河-西山断裂、龙门山断裂带北段汉中盆地活动构造系和南段大川-双石断裂为地表弱活动断裂,潜在震级6.5~7.0,陇县-宝鸡断裂带的桃园-龟川寺、固关-虢镇以及陇县-岐山-马召断裂潜在震级依次为6.0~6.5、6.5~7.0、7.5级左右。
In general,the displacement produced by a magnitude 6~7 earthquake is relatively small,even does not reach the surface,so it is difficult to be preserved in geological records.On the other hand,the seismogenic fault of such earthquakes is easy to be considered incorrectly as a non-active fault since Holocene,consequently overlooking the real seismic hazard in the future.To solve this problem,we propose a type of faults that are capable of generating M6~7 earthquakes,but with weak surface activity and cannot produce conspicuous surface displacement.To recognize such faults from geological records,which have no visible evidence of activity since middle-late Pleistocene,is the key to intermediate-and long-term earthquake prediction.The specific procedures of the technology are as follows:First,we determine the seismotectonic setting of the tectonic system in which the target fault lies.Second,we establish the relation between the target fault and other active faults in the same tectonic system,which have records of historical earthquakes or paleoearthquakes.Then we compare varied seismogenic units in the same-order structure,same tectonic system,and varied stages in the same tectonic process.The case studies demonstrate that this is an effective method for intermediate-and long-term earthquake prediction.The cases studied include the Puduhe-Xishan Fault in Kunming City,Hanzhong Basin in the north section of the Longmen Shan Fault zone,Dachuan-Shuangshi Fault in the south section of the Longmen Shan Fault zone,and the Guguan-Guoshun Fault of the LongxianBaoji Fault zone.These faults all show weak activities on the surface and have potential for earthquakes with estimated magnitude 6.5~7.0.In addition,by estimation using this method,the TaoyuanGuichuan Fault of the Longxian-Baoji Fault zone has a seismic risk of M6.0~6.5 earthquake,and the Longxian-Qima-Mazhao Fault is capable of producing an earthquake about M7.5.
In general,the displacement produced by a magnitude 6~7 earthquake is relatively small,even does not reach the surface,so it is difficult to be preserved in geological records.On the other hand,the seismogenic fault of such earthquakes is easy to be considered incorrectly as a non-active fault since Holocene,consequently overlooking the real seismic hazard in the future.To solve this problem,we propose a type of faults that are capable of generating M6~7 earthquakes,but with weak surface activity and cannot produce conspicuous surface displacement.To recognize such faults from geological records,which have no visible evidence of activity since middle-late Pleistocene,is the key to intermediate-and long-term earthquake prediction.The specific procedures of the technology are as follows:First,we determine the seismotectonic setting of the tectonic system in which the target fault lies.Second,we establish the relation between the target fault and other active faults in the same tectonic system,which have records of historical earthquakes or paleoearthquakes.Then we compare varied seismogenic units in the same-order structure,same tectonic system,and varied stages in the same tectonic process.The case studies demonstrate that this is an effective method for intermediate-and long-term earthquake prediction.The cases studied include the Puduhe-Xishan Fault in Kunming City,Hanzhong Basin in the north section of the Longmen Shan Fault zone,Dachuan-Shuangshi Fault in the south section of the Longmen Shan Fault zone,and the Guguan-Guoshun Fault of the LongxianBaoji Fault zone.These faults all show weak activities on the surface and have potential for earthquakes with estimated magnitude 6.5~7.0.In addition,by estimation using this method,the TaoyuanGuichuan Fault of the Longxian-Baoji Fault zone has a seismic risk of M6.0~6.5 earthquake,and the Longxian-Qima-Mazhao Fault is capable of producing an earthquake about M7.5.
引文
陈国光,计凤桔,周荣军,等.2007.龙门山断裂带晚第四纪活动性分段的初步研究[J].地震地质,29(3):657 —673.CHEN Guo-guang,JI Feng-ju,ZHOU Rong-jun et al.2007.Primary research of activity segmentation of Longmenshan Fault zone since late-Quaternary[J].Seismology and Geology,29(3):657—673(in Chinese).
陈立春,陈杰,刘进峰,等.2008.龙门山前山断裂北段晚第四纪活动性研究[J].地震地质,30(3):710—722.CHEN Li-chun,CHEN Jie,LIU Jin-feng,et al.2008.Investigation of late Quaternary activity along the northern frontrange fault,Longmenshan[J].Seismology and Geology,30(3):710—722(in Chinese).
邓起东,于贵华,叶文华,等.1992.地震地表破裂参数与震级关系的研究[A].见:国家地震局地质研究所编.活动断裂研究(2).北京:地震出版社.247—264.DENG Qi-dong,YU Gui-hua,YE Wen-hua,et al.1992.Relationship between earthquake magnitude and parameters of surface rupture associated with historical earthquakes[A].In:Institute of Geology,SSB(ed).Research of Active Fault(2).Seismological Press,Beijing.247—264(in Chinese).
樊春,王二七,王刚,等.2008.龙门山断裂带北段晚新近纪以来的右行走滑运动及其构造变换研究:以青川断裂为例[J].地质科学.43(3):417—433.FAN Chun,WANG Er-qi,WANG Gang,et al.2008.Dextral strike-slip and tectonic transformation of the northern Longmen Shan Fault belt from late Neogene:A case study from the Qingchuan Fault[J].Chinese Journal of Geology,43 (3):417—433(in Chinese).
李传友,宋方敏,冉勇康.2004.龙门山断裂带北段晚第四纪活动性讨论[J].地震地质,26(2):248—258.LI Chuan-you,SONG Fang-min,RAN Yong-kang.2004.Late Quaternary activity and age constraint of the northern Longmenshan Fault zone[J].Seismology and Geology,26(2):248—258(in Chinese).
冉勇康,陈立春,陈桂华,等.2008.汶川MS8 .0地震发震断裂大地震原地重复现象初析[J].地震地质,30(3):630 —643.RAN Yong-kang,CHEN Li-chun,CHEN Gui-hua,et al.2008.Primary analyses of in-situ recurrence of large earthquake along seismogenic fault of the M S8 .0 Wenchuan earthquake[J].Seismology and Geology,30(3):630—643(in Chinese).
杨晓平,冯希杰,戈天勇,等.2008.龙门山断裂带北段第四纪活动的地质地貌证据[J].地震地质,30(3):644 —657.YANG Xiao-ping,FENG Xi-jie,GE Tian-yong,et al.2008.Geological and geomorphic evidence for the Quaternary activity on the northeast segment of Longmenshan Fault zone[J].Seismology and Geology,30(3):644—657(in Chinese).
杨晓平,蒋溥,宋方敏.1999.龙门山断裂带南段错断晚更新世以来地层的证据[J].地震地质,21(4):341—345 .YANG Xiao-ping,JIANG Pu,SONG Fang-min.1999.The evidence of the south Longmenshan Fault zone cutting late Quaternary stratum[J].Seismology and Geology,21(4):341—345(in Chinese).
中国地震局.2009.活动断层探测(DB/T15-2009)[S].北京:标准出版社.China Earthquake Administration.2009.Surveying and Prospecting of Active Fault(DB/T15-2009)[S].China Standards Press,Beijing(in Chinese).
中国地震局.2005.中国地震活动断层探测技术系统技术规程[M].北京:地震出版社.China Earthquake Administration.2005.Stipulation on Technical System for China Earthquake Active Fault Surveying[M].Seismological Press,Beijing(in Chinese).
Lichun Chen,Yongkang Ran,Hu Wang,et al.2013.Palaeoseismology and kinematics characteristics of the Xiaoyudong rupture,a short but significant strange segment characterized by the May 12,2008,M W7 .9 earthquake in Sichuan,China[J].Tectonophysics,584:91—101.
Schwartz D P,Coppersmith K J.1984.Fault behaviour and characteristic earthquakes:Examples from the Wasatch and San Andreas Fault zones[J].J Geophys Res,90:5681—5698.
Wells D L,Coppersmith K J.1994.New empirical relationships among magnitude,rupture length,rupture width,rupture area,and surface displacement[J].B S S A,84:974—1002.
Yongkang Ran,Lichun Chen,Jie Chen,et al.2010.Paleoseismic evidence and repeat time of large earthquakes at three sites along the Longmenshan Fault zone[J].Tectonophysics,491:141—153.doi:10.1016/j.tecto.2010.01.009.
Yongkang Ran,Wenshan Chen,Xiwei Xu,et al.2013.Paleoseismic events and recurrence interval along the BeichuanYingxiu Fault of Longmenshan Fault zone,Yingxiu,Sichuan,China[J].Tectonophysics,584:81—90.
①中国地震局地质研究所,2007,昆明市目标区主要断裂地震危险性评价(工作报告)。
①中国地震局地质研究所,2012,汉中市目标区主要断裂地震危险性评价(工作报告)。
②同482页①。
③中国地震局地质研究所,2008,汶川8.0级地震科学考察项目“汶川地震的发震构造与断裂活动性调查”(科研报告)。
④中国地震局地质研究所,2011,雅安市主要活动断裂调查与填图项目成果报告(工作报告)。
①中国地震局地质研究所,2012,宝鸡市目标区主要断裂地震危险性评价(工作报告)。
陈立春,陈杰,刘进峰,等.2008.龙门山前山断裂北段晚第四纪活动性研究[J].地震地质,30(3):710—722.CHEN Li-chun,CHEN Jie,LIU Jin-feng,et al.2008.Investigation of late Quaternary activity along the northern frontrange fault,Longmenshan[J].Seismology and Geology,30(3):710—722(in Chinese).
邓起东,于贵华,叶文华,等.1992.地震地表破裂参数与震级关系的研究[A].见:国家地震局地质研究所编.活动断裂研究(2).北京:地震出版社.247—264.DENG Qi-dong,YU Gui-hua,YE Wen-hua,et al.1992.Relationship between earthquake magnitude and parameters of surface rupture associated with historical earthquakes[A].In:Institute of Geology,SSB(ed).Research of Active Fault(2).Seismological Press,Beijing.247—264(in Chinese).
樊春,王二七,王刚,等.2008.龙门山断裂带北段晚新近纪以来的右行走滑运动及其构造变换研究:以青川断裂为例[J].地质科学.43(3):417—433.FAN Chun,WANG Er-qi,WANG Gang,et al.2008.Dextral strike-slip and tectonic transformation of the northern Longmen Shan Fault belt from late Neogene:A case study from the Qingchuan Fault[J].Chinese Journal of Geology,43 (3):417—433(in Chinese).
李传友,宋方敏,冉勇康.2004.龙门山断裂带北段晚第四纪活动性讨论[J].地震地质,26(2):248—258.LI Chuan-you,SONG Fang-min,RAN Yong-kang.2004.Late Quaternary activity and age constraint of the northern Longmenshan Fault zone[J].Seismology and Geology,26(2):248—258(in Chinese).
冉勇康,陈立春,陈桂华,等.2008.汶川MS8 .0地震发震断裂大地震原地重复现象初析[J].地震地质,30(3):630 —643.RAN Yong-kang,CHEN Li-chun,CHEN Gui-hua,et al.2008.Primary analyses of in-situ recurrence of large earthquake along seismogenic fault of the M S8 .0 Wenchuan earthquake[J].Seismology and Geology,30(3):630—643(in Chinese).
杨晓平,冯希杰,戈天勇,等.2008.龙门山断裂带北段第四纪活动的地质地貌证据[J].地震地质,30(3):644 —657.YANG Xiao-ping,FENG Xi-jie,GE Tian-yong,et al.2008.Geological and geomorphic evidence for the Quaternary activity on the northeast segment of Longmenshan Fault zone[J].Seismology and Geology,30(3):644—657(in Chinese).
杨晓平,蒋溥,宋方敏.1999.龙门山断裂带南段错断晚更新世以来地层的证据[J].地震地质,21(4):341—345 .YANG Xiao-ping,JIANG Pu,SONG Fang-min.1999.The evidence of the south Longmenshan Fault zone cutting late Quaternary stratum[J].Seismology and Geology,21(4):341—345(in Chinese).
中国地震局.2009.活动断层探测(DB/T15-2009)[S].北京:标准出版社.China Earthquake Administration.2009.Surveying and Prospecting of Active Fault(DB/T15-2009)[S].China Standards Press,Beijing(in Chinese).
中国地震局.2005.中国地震活动断层探测技术系统技术规程[M].北京:地震出版社.China Earthquake Administration.2005.Stipulation on Technical System for China Earthquake Active Fault Surveying[M].Seismological Press,Beijing(in Chinese).
Lichun Chen,Yongkang Ran,Hu Wang,et al.2013.Palaeoseismology and kinematics characteristics of the Xiaoyudong rupture,a short but significant strange segment characterized by the May 12,2008,M W7 .9 earthquake in Sichuan,China[J].Tectonophysics,584:91—101.
Schwartz D P,Coppersmith K J.1984.Fault behaviour and characteristic earthquakes:Examples from the Wasatch and San Andreas Fault zones[J].J Geophys Res,90:5681—5698.
Wells D L,Coppersmith K J.1994.New empirical relationships among magnitude,rupture length,rupture width,rupture area,and surface displacement[J].B S S A,84:974—1002.
Yongkang Ran,Lichun Chen,Jie Chen,et al.2010.Paleoseismic evidence and repeat time of large earthquakes at three sites along the Longmenshan Fault zone[J].Tectonophysics,491:141—153.doi:10.1016/j.tecto.2010.01.009.
Yongkang Ran,Wenshan Chen,Xiwei Xu,et al.2013.Paleoseismic events and recurrence interval along the BeichuanYingxiu Fault of Longmenshan Fault zone,Yingxiu,Sichuan,China[J].Tectonophysics,584:81—90.
①中国地震局地质研究所,2007,昆明市目标区主要断裂地震危险性评价(工作报告)。
①中国地震局地质研究所,2012,汉中市目标区主要断裂地震危险性评价(工作报告)。
②同482页①。
③中国地震局地质研究所,2008,汶川8.0级地震科学考察项目“汶川地震的发震构造与断裂活动性调查”(科研报告)。
④中国地震局地质研究所,2011,雅安市主要活动断裂调查与填图项目成果报告(工作报告)。
①中国地震局地质研究所,2012,宝鸡市目标区主要断裂地震危险性评价(工作报告)。
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心