夏垫断裂大胡庄探槽古地震事件分析  

Analysis of Paleoseismic Events of the Dahuzhuang Trench at the Xiadian Fault

作　　者：邓梅[1] 沈军[1] 李西[2] 祁高[1] 戴训也 王昌盛[1] 刘泽众 DENG Mei;SHEN Jun;LI Xi;QI Gao;DAI Xunye;WANG Changsheng;LIU Zezhong(Institute of Disaster Prevention,Yanjiao 065201,Hebei,China;Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)

机构地区：[1]防灾科技学院,河北燕郊065201 [2]云南省地震局,云南昆明650224

出　　处：《地震研究》2018年第2期293-301,共9页Journal of Seismological Research

基　　金：国家自然科学基金项目(41372216);中央高校基本科研业务费研究生科技创新项目(ZY20170313)联合资助

摘　　要：夏垫断裂是北京平原区内1条极为重要的隐伏活动断裂,同时也是1679年三河—平谷MS8.0地震的发震断层。为获取该断裂完整的古地震序列,主要开展了2方面工作:(1)以大胡庄探槽原始资料为基础,重新对探槽进行了解译,共识别出3个埋藏古土壤,6个崩积楔和1次砂土液化现象;(2)结合该断裂其它部位探槽揭示的古地震事件,通过对比各探槽标志性地层,建立不同探槽中古地震事件在同一时间轴上的联系,得到夏垫断裂完整的古地震序列。结果表明:距今31 ka以来,夏垫断裂共发生过11次古地震事件,古地震平均复发间隔约为2.8ka,但距今25~15 ka存在1个古地震丛集期,丛集期内共发生5次强震,平均复发间隔约为2.0 ka,反映出夏垫断裂活动性存在阶段性的差异。The Xiadian fault is an important buried active fault located in the Beijing plain. It is also the seismogenic fault of the Sanhe-Pinggu MS8. 0 earthquake occurred in 1679. In order to obtain the complete paleoseismic sequence of the fault,the following two aspects are carried out. First,we reinterpret the Dahuzhuang trench based on the origin trench datum and reveal three paleosol,six collapse wedges and one sand liquefaction. Second,combined with the events revealed by the trenches in other parts of the fault,we established the relationship between the seismic events of different trenches at the same time axis. Then,we get intact paleoseismic sequence of the Xiadian fault. The results showthat the Xiadian fault has occurred 11 paleoseismic events（including the1679 earthquake） since 31 ka and the average recurrence interval of earthquake was 2. 82 ka. Meanwhile,there were five strong earthquakes from 25 ka to 15 ka and the average recurrence interval was 2 ka. It reflects that the activity of the Xiadian fault exists differences at different stages.

关 键 词：夏垫断裂 古地震事件 崩积楔 砂土液化 标志性地层 

分 类 号：P315.21[天文地球—地震学]