钻探揭示的黄河断裂北段活动性和滑动速率  

ACTIVITY AND SLIP RATE OF THE NORTHERN SECTION OF YELLOW RIVER FAULT REVEALED BY DRILLING

作　　者：雷启云[1,2] 柴炽章[2] 郑文俊[1] 杜鹏[2] 谢晓峰[2] 王银[2] 崔瑾[2] 孟广魁[2] 

机构地区：[1]中国地震局地质研究所地震动力学国家重点实验室,北京100029 [2]宁夏回族自治区地震局,银川750001

出　　处：《地震地质》2014年第2期464-477,共14页Seismology and Geology

基　　金：中国地震局地震行业专项(201308012,201008003);国家自然科学基金(41202158)共同资助

摘　　要：黄河断裂是银川盆地内展布最长、切割最深的一条深大断裂,也是银川盆地的东边界。由于其北段呈隐伏状,因此,该段的活动性和滑动速率长期未知,影响了对盆地演化和地震危险性的认识。文中选择具有石油地震勘探基础的陶乐镇为研究场点,以人工浅层地震勘探结果为依据,在黄河断裂北段布设了一排钻孔联合剖面,并对标志层进行年代测试,获得了断裂的活动时代和滑动速率。结果表明,黄河断裂北段在晚更新世末期或全新世有过活动,在(28.16±0.12)ka BP以来的累积位移为0.96m,晚第四纪以来的平均滑动速率为0.04mm/a,该值明显低于南段灵武断层(0.24mm/a);尽管向下切割了莫霍面,黄河断裂晚第四纪活动强度和发震能力均要低于切割相对浅的贺兰山东麓断裂;黄河断裂可能在新生代之前已经强烈活动并深切莫霍面,新生代以来,银川盆地的构造活动迁移分解到以贺兰山东麓断裂为主的多条断裂之上,地壳双层伸展模型可解释银川盆地现今深浅部构造活动间的联系。Yellow River Fault is the longest, deepest boundary of the basin. Because its north section is which made a negative impact on understanding fauh in the Yinchuan Basin, also is the eastern buried, its activity and slip rate remains unknown, the evolution and seismic hazard of the Yinchuan Basin. In this study, a composite drilling section with a row of drillholes were laid out along the northern section of the Yellow River Fault based on the results of shallow seismic exploration near the Taole Town, where oil seismic exploration data are available. Fault activity and slip rate are obtained by measuring the age of samples of holes. The results show that the northern section of the Yellow River Fault is a late Pleistocene or Holocene Fault, （28.16-＋0.12）ka BP, with an average slip rate of 0. southern section. The activity intensity of the northern its accumulative displacement is 0.96m since 04mm/a, which is significantly lower than the section of the Yellow River Fault is significantly lower than the southern section since Late Quaternary. In the Yinchuan Basin, the Helanshan eastern piedmont fault is the most active fault since late Quaternary, next is the Yellow River Fault, then, the Yinchuan buried fault and Luhuatai buried fault. Although the Yellow River Fault is the deepest and the longest fault, its maximum potential earthquake is magnitude 7, this seismogenic capability is weaker than the relatively shallower Helanshan eastern piedmont fault, on which occurred the Pingluo M8 earthquake in 1739 AD. Yinchuan Basin is the result of long-term activities of the four major faults, which shaped the special structure of the different parts of Yinchuan Basin. The Yellow River Fault controlled the evolution of the south part of Yinchuan Basin. The two-layer crustal stretching model can help us understand the structural deformation between the upper crust and the lower crust beneath Yinchuan Basin. Deformation of the upper crust is controlled by several brittle normal faults, while the deformation of the lowe

关 键 词：黄河断裂 钻探 滑动速率 银川盆地 

分 类 号：P315.2[天文地球—地震学]