皇城—双塔断裂冬青顶段古地震活动规律的初步研究
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摘要
冬青顶断裂段位于甘肃古浪皇城—双塔断裂的东段 ,由南北两条向北东方向呈弧形突出的近于平行的断裂组成。北断裂为挤压特征的逆冲断层 ,全长约 4 0km ,南断裂为具张性特征的正断层 ,全长约 34km ,二者具有内在的成生联系。该断裂全新世以来有过明显的构造活动。通过沿断裂带的追踪考察 ,在冬青顶断裂段上 ,开挖了 3个大型探槽 ,经综合对比发现该断裂近 15 0 0 0a以来共发生过 3次古地震事件和 1次历史地震事件 ,其发生年代分别是 :事件Ⅰ 15 930± 116 0aB P ,事件Ⅱ 94 6 0± 70 0aB P ,事件Ⅲ 5 0 0 0± 5 0 0aB P ,事件Ⅳ应是 192 7年古浪 8级大地震 (为历史地震事件 )。这 4次事件在时空分布上具有明显的准周期复发特征
Dongqingding segment lies in the east part of Huangcheng-Shuangta active fault at Gulang County in Gangsu Province. It is consisted of two nearly-paralleled arch faults which protrude in northeast direction. One fault lies in the north and another fault lies in the south. The north fault is a compressional thrust fault that is about 40km long and the south one is a tensional normal fault that is about 34km long. Since Holocene, there have been obvious constructive activities on the fault. Based on forerunners'researches and the recent field investigation, three trenches have been dug on two chosen sites of the fault. The contrast results reveal that three palaeo-earthquakes and one historical-earthquake had occurred on the fault in the past 15,000 years. The age of the first earthquake is 15,930±1,160 years. The age of the second earthquake is 9,460±700 years. The age of the third earthquake is 5,000±500 years. The fourth earthquake must be the Gulang Ms 8.0 Earthquake which occurred in 1927. The four seismic events are obviously the approximate recurrent events with regard to the spatio-temporal distribution.
Dongqingding segment lies in the east part of Huangcheng-Shuangta active fault at Gulang County in Gangsu Province. It is consisted of two nearly-paralleled arch faults which protrude in northeast direction. One fault lies in the north and another fault lies in the south. The north fault is a compressional thrust fault that is about 40km long and the south one is a tensional normal fault that is about 34km long. Since Holocene, there have been obvious constructive activities on the fault. Based on forerunners'researches and the recent field investigation, three trenches have been dug on two chosen sites of the fault. The contrast results reveal that three palaeo-earthquakes and one historical-earthquake had occurred on the fault in the past 15,000 years. The age of the first earthquake is 15,930±1,160 years. The age of the second earthquake is 9,460±700 years. The age of the third earthquake is 5,000±500 years. The fourth earthquake must be the Gulang Ms 8.0 Earthquake which occurred in 1927. The four seismic events are obviously the approximate recurrent events with regard to the spatio-temporal distribution.
引文
国家地震局兰州地震研究所.祁连山活动裂1∶5万地质填图和特征地震研究报告(85-02-1-3-4)—古浪活动断裂带1∶5万地质图说明书及图集.1995.
国家地震局兰州地震研究所.祁连山活动裂1∶5万地质填图和特征地震研究报告(85-02-1-3-4)—古浪活动断裂带1∶5万地质图说明书及图集.1995.
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[2]刘洪春,贾云鸿,陈永明,等.1927年古浪8级地震地表破裂带研究[A ].活动断裂研究(4)[M].北京:地震出版社,1995.79-91.
[3]刘洪春,贾云鸿,苏向洲,等.皇城—双塔活动断裂分段及不均匀性研究[A].活动断裂研究(5)[M].北京:地震出版社,1996.87-94.
[4]贾云鸿,苏向洲,刘洪春,等.皇城—双塔断裂东段(祁连—双塔段)晚更新世以来的活动特征.活动断裂研究(3)[M].北京:地震出版社,1994.170-179.
[5]Y .Gaudemer,P .Tapponnier,B .Meyer,etal.Partitioningofcrustalslipbetweenlinked,activefaultsintheeasternQilianshan,andevidenceforamajorseismicgap,the’Tianzhugap’,onthewesternHaiyuanFault,Gansu(China)[J].GeophysicalJournal,1995.120(3):599-645.
[6]侯康明,邓起东,刘百篪.冬青顶活动背斜的变形样式、变形幅度及形成机理[A].活动断裂研究(6)[M].北京:地震出版社,1997.88-96.
[7]毛凤英,张培震.古地震研究的逐次限定法与新疆北部主要断裂带的古地震研究[A].活动断裂研究(4)[M].北京:地震出版社,1995.153-164.
国家地震局兰州地震研究所.祁连山活动裂1∶5万地质填图和特征地震研究报告(85-02-1-3-4)—古浪活动断裂带1∶5万地质图说明书及图集.1995.
[1]侯康明.1927年古浪8级大震的发震构造条件形成机制及区域动力学环境研究[D].北京:国家地震局地质研究所,1996.
[2]刘洪春,贾云鸿,陈永明,等.1927年古浪8级地震地表破裂带研究[A ].活动断裂研究(4)[M].北京:地震出版社,1995.79-91.
[3]刘洪春,贾云鸿,苏向洲,等.皇城—双塔活动断裂分段及不均匀性研究[A].活动断裂研究(5)[M].北京:地震出版社,1996.87-94.
[4]贾云鸿,苏向洲,刘洪春,等.皇城—双塔断裂东段(祁连—双塔段)晚更新世以来的活动特征.活动断裂研究(3)[M].北京:地震出版社,1994.170-179.
[5]Y .Gaudemer,P .Tapponnier,B .Meyer,etal.Partitioningofcrustalslipbetweenlinked,activefaultsintheeasternQilianshan,andevidenceforamajorseismicgap,the’Tianzhugap’,onthewesternHaiyuanFault,Gansu(China)[J].GeophysicalJournal,1995.120(3):599-645.
[6]侯康明,邓起东,刘百篪.冬青顶活动背斜的变形样式、变形幅度及形成机理[A].活动断裂研究(6)[M].北京:地震出版社,1997.88-96.
[7]毛凤英,张培震.古地震研究的逐次限定法与新疆北部主要断裂带的古地震研究[A].活动断裂研究(4)[M].北京:地震出版社,1995.153-164.
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