华北平原中南部聊城-兰考断裂的第四纪晚期活动性探测——兼论1937年菏泽7.0级地震发震机制  

Detection of the Late Quaternary activity of the Liaocheng-Lankao Fault in the south-central part of the North China Plain:Discussion on the seismogenic mechanism of the 1937 Heze M 7.0 earthquake

作　　者：刘广英 梁宽 李志鹏 马保起 龙焘 李磊 谭鑫 李浩洋 LIU Guangying;LIANG Kuan;LI Zhipeng;MA Baoqi;LONG Tao;LI Lei;TAN Xin;LI Haoyang(China Railway Design Corporation,Tianjin 300308,China;National Institute of Natural Hazards,Ministry of Emergency Management of China,Beijing 100085,China;Key Laboratory of Compound and Chained Natural Hazards Dynamics,Ministry of Emergency Management of China,Beijing 100085,China;University of Chinese Academy of Sciences,School of Emergency Management Science and Engineering,Beijing 100049,China;Sichuan Water Conservancy College,Chengdu 611231,Sichuan,China)

机构地区：[1]中国铁路设计集团有限公司,天津300308 [2]应急管理部国家自然灾害防治研究院,北京100085 [3]复合链生自然灾害动力学应急管理部重点实验室,北京100085 [4]中国科学院大学应急管理工程与科学学院,北京100049 [5]四川水利职业技术学院,四川成都611231

出　　处：《地质力学学报》2024年第2期242-259,共18页Journal of Geomechanics

基　　金：国家自然科学基金项目(42202253);应急管理部国家自然灾害防治研究院基本科研业务专项(ZDJ2019-28,ZDJ2019-21);中国铁路设计集团有限公司科技开发计划(2020YY340411)。

摘　　要：华北平原是中国人口最多、经济最为发达的地区之一,也是受地震灾害影响最为严重的地区之一。对于该地区断裂活动性和大地震发震机制的研究有利于探索板内地震的发震规律、减轻地震灾害所造成的损失。聊城-兰考断裂是华北平原中南部一条重要的隐伏深大断裂。结合浅层地震勘探、钻孔勘探和第四纪测年方法,对聊城-兰考断裂的活动性进行了精细的研究。坝城寺钻孔揭示聊城-兰考断裂南段错断了全新统底界,为全新世早期活动断裂,揭露出该断裂晚更新世以来造成了4次古地震事件,单次事件的垂直位错为1.2±0.2~3.7±0.2 m。根据钻孔揭示的地层落差计算出该断裂晚更新世早期的平均垂直滑动速率约为0.1±0.05 mm/a,晚更新世晚期—全新世中期的平均滑动速率为0.35±0.04 mm/a。根据1937年菏泽7.0级和6(3/4)级地震的等震线和地表破裂分布特征认为,小留-解元集断裂和东明-成武断裂为该地震的发震断裂;聊城-兰考断裂对于该地区应力的积累、地震的发生具有很好的控制和约束作用,为区域控震构造。[Objective]The North China Plain(NCP)is one of the most populated and economically developed areas in China and is a region with a high level of seismic hazards.Studying the Quaternary activity of the faults and the seismogenic mechanism of the large earthquakes in NCP is conducive to exploring the seismogenic pattern of intraplate earthquakes and reducing the damage caused by seismic hazards.The Liaocheng-Lankao fault(LLF)is an important buried deep major fault in the south-central part of the NCP.The activity of the LLF and its relationship with the 1937 Heze M 7.0 earthquake is still highly controversial.[Methods]In this study,the activity of the Liaocheng-Liaokao fault is finely studied by combining shallow seismic exploration,drilling,and Quaternary dating methods.[Results]Shallow seismic reflection profile ZF-2 reveals that the strata below 145 m are obviously displaced,and the strata above 145 m are disturbed.The Bachengsi drilling profile reveals 16 sets of marker layers and three west-dipping normal faults Fa,Fb,and Fc;they form a“compound Y”structure in the profile,of which Fa displaces the bottom boundary of the Holocene(burial depth of approximately 38.9 m)and is an early Holocene active fault.It also reveals four paleoseismic events since the Late Pleistocene,with vertical displacement of 1.2±0.2 to 3.7±0.2 m for a single event.Based on the stratigraphic offsets in the boreholes,the average vertical slip rate of this fault is calculated to be about 0.1±0.05 mm/a for the early Late Pleistocene and 0.35±0.04 mm/a for the late Late Pleistocene-middle Holocene.The fitted age-depth curves by the test results of seven 14C samples and four OSL samples can be divided into two segments.Within the depth range of 0 to 86.0 m(approximately 21 to 0 ka),the age and depth of the strata conform to the formula y=(253.69±16.56)x+(924.72±681.36),from which the average deposition rate of this section is calculated to be 3.94±0.26 mm/a.Within the depth range of 102.9 to 145.4 m(approximately 128 to 59 ka),the

关 键 词：华北平原 聊城-兰考断裂 浅层地震探测剖面 钻孔联合剖面 1937年菏泽7.0级地震 

分 类 号：P65[天文地球—地质学]