四川小金抚边河断裂的晚第四纪活动特征
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摘要
１９８９ 年９ 月２２ 日小金６－６ 级地震和本次地震的前震（１９８９ 年３ 月１ 日的５－０ 级）及余震（１９９１ 年２ 月１８ 日的５－０ 级） 均发生于小金两河口—木城附近， 这３ 次地震的震中连线及其等烈度线长轴皆大致呈Ｎ３０°Ｗ 方向， 暗示着该区存在北西向的活动构造。本文在航空照片判译和野外实地调查的基础上， 初步查明了抚边河断裂的空间展布特征。通过断错地貌的研究， 结合热释光（ＴＬ） 测龄结果， 首次发现了抚边河断裂晚第四纪以来以左旋走滑运动为主， 并兼具一定倾滑分量的地质证据， 其平均水平滑动速率在１－３ ±０－１ｍｍ／ａ 左右。最后讨论了抚边河断裂的可能地震能力。
Xiaojin M6 6 earthquake on Sept. 22, 1989 and its foreshock(March 1, 1989 M5 0), aftershock(Feb. 18, 1991 M5 0)all occurred in the zone of Lianghekou Mucheng, Xiaojin County. The line contacting the three epicenters and their major axis of intensity isolines all distributed along the orientation of N30W approximately. This implies there is an active structure of NW direction in the area. On the basis of investigating the aerial photos and sites, this paper makes the spatial distribution features of Fubianhe fault clear. Through studying rapture topography and the result of TL method, the paper first proposes some geological evidences that Fubianhe fault is a left lateral fault with some dip slip component since late Quaternary, and the average slip-rate of the fault is about 1 3(0 1 mm/a. In the end of the paper, the capability of occurring earthquake of Fubianhe fault was discussed.
Xiaojin M6 6 earthquake on Sept. 22, 1989 and its foreshock(March 1, 1989 M5 0), aftershock(Feb. 18, 1991 M5 0)all occurred in the zone of Lianghekou Mucheng, Xiaojin County. The line contacting the three epicenters and their major axis of intensity isolines all distributed along the orientation of N30W approximately. This implies there is an active structure of NW direction in the area. On the basis of investigating the aerial photos and sites, this paper makes the spatial distribution features of Fubianhe fault clear. Through studying rapture topography and the result of TL method, the paper first proposes some geological evidences that Fubianhe fault is a left lateral fault with some dip slip component since late Quaternary, and the average slip-rate of the fault is about 1 3(0 1 mm/a. In the end of the paper, the capability of occurring earthquake of Fubianhe fault was discussed.
引文
〔1〕四川省地震局- 一九八九年四川小金地震- 成都: 四川科学技术出版社-1993 , 73 —113
〔2〕何玉林, 龚宇, 伍先国- 四川抚边河断裂的活动特征- 地震地质, 1997 , 19 (1) : 31 —36
〔3〕龚宇, 何玉林, 伍先国- 抚边河断裂新活动特征的探讨- 四川地震, 1995 , (4) : 31 —36
〔4〕丁国瑜主编- 中国岩石圈动力学概论- 北京: 地震出版社, 1991-142 —148
〔5〕唐荣昌, 韩渭滨主编- 四川活动断裂与地震- 北京: 地震出版社, 1993 , 229 —272
〔6〕Barka, A. A., and K. Kadinsky - Cade , Strike - slip fault geometry in Turkey and its influence on earthquake activity ,Tectonics, Vol. 7 , NO. 3 , 1988
〔7〕Crone, A. J., and M. Machetts, Surfacefaulting accompanying the Borah Peak earthquake,CentralIdaho, Geology, 12 ,1984
〔8〕周荣军, 马声浩, 蔡长星- 甘孜—玉树断裂带的晚第四纪活动性- 中国地震, 1996, 2 (3)
〔9〕闻学泽- 活动断裂地震潜势的定量评估- 北京: 地震出版社, 1995-230 —42
〔2〕何玉林, 龚宇, 伍先国- 四川抚边河断裂的活动特征- 地震地质, 1997 , 19 (1) : 31 —36
〔3〕龚宇, 何玉林, 伍先国- 抚边河断裂新活动特征的探讨- 四川地震, 1995 , (4) : 31 —36
〔4〕丁国瑜主编- 中国岩石圈动力学概论- 北京: 地震出版社, 1991-142 —148
〔5〕唐荣昌, 韩渭滨主编- 四川活动断裂与地震- 北京: 地震出版社, 1993 , 229 —272
〔6〕Barka, A. A., and K. Kadinsky - Cade , Strike - slip fault geometry in Turkey and its influence on earthquake activity ,Tectonics, Vol. 7 , NO. 3 , 1988
〔7〕Crone, A. J., and M. Machetts, Surfacefaulting accompanying the Borah Peak earthquake,CentralIdaho, Geology, 12 ,1984
〔8〕周荣军, 马声浩, 蔡长星- 甘孜—玉树断裂带的晚第四纪活动性- 中国地震, 1996, 2 (3)
〔9〕闻学泽- 活动断裂地震潜势的定量评估- 北京: 地震出版社, 1995-230 —42
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