江苏盐城-南洋岸隐伏断裂第四纪活动性研究  

Research on Quaternary Activity of the Yancheng-Nanyang’anBuried Fault in Jiangsu Province

作　　者：张硕 张平[1] 龚绪龙[1] 于军[1] ZHANG Shuo;ZHANG Ping;GONG Xulong;YU Jun(Geological Survey of Jiangsu Province,Nanjing 210018,China)

机构地区：[1]江苏省地质调查研究院,南京市210018

出　　处：《大地测量与地球动力学》2023年第7期722-727,共6页Journal of Geodesy and Geodynamics

基　　金：江苏1:5万盐城市、引水沟、龙王庙、伍佑镇、大丰县、裕华镇幅区调项目(1212011220536);江苏沿海综合地质调查项目。

摘　　要：在综合分析区内重力和石油物探等资料基础上,采用浅层地震勘探和钻探等方法对盐城-南洋岸断裂空间展布及第四纪活动性进行研究。结果表明,盐城-南洋岸断裂由2条断裂组成,其中主断裂倾向NNW,倾角约65°~80°;次级断裂呈弧形发育于新洋北侧一带,倾角约70°~80°;2条断裂均为正断层,上陡下缓。浅地震探测查明盐城-南洋岸断裂及其次级断裂在盐城市主城区东侧的准确位置,重力布格异常解译显示主断裂向SW方向延伸。盐城-南洋岸断裂主断裂明显的断裂位错变动向上可切达地表以下约70 m,断裂控制地层发育的上限层位达地表以下约55~70 m。综合钻孔和浅层地震勘探资料,对比分析周边同构造环境同走向断裂,判断盐城-南洋岸断裂为早中更新世隐伏断裂。对盐城-南洋岸断裂附近中强震资料记录进行收集投影,发现该断裂附近发生过3次中强震,地震活动与断裂具有明显的相关性,该断裂未来的潜在地震危险性值得重视。Based on the comprehensive analysis of gravity and petroleum geophysical exploration data,we study the spatial distribution and Quaternary activity of Yancheng-Nanyang’an fault by shallow seismic exploration and drilling.The results show that the Yancheng-Nanyang’an fault is composed of two faults.The tendency of main fault is NNW and the dip is about 65°-80°.The secondary fault is arc-shaped in the north of Xinyang,with a dip of 70°-80°.Both faults are normal,the upper part is steep and the lower part is slow.The shallow seismic exploration identified the exact position of Yancheng-Nanyang’an fault and its secondary fault in the main urban area of Yancheng.The gravity Bouguer anomaly interpretation shows that the main fault extends in a SW direction.The obvious fracture dislocation variation of the main fault of Yancheng-Nanyang’an fault is about 70 m below the surface,and the upper limit stratum controlled by fault is about 55-70 m below the surface.Based on the shallow seismic exploration and borehole data,we compare and analyze the surrounding faults with the same tectonic environment and strike,the Yancheng-Nanyang’an fault is judged to be an early-middle Pleistocene buried fault.The moderate-strong earthquakes data near Yancheng-Nanyang’an fault shows that there have occurred three earthquakes near the fault.There is an obvious correlation between the earthquakes and Yancheng-Nanyang’an fault,and the future potential earthquake risk is worthy of attention.

关 键 词：盐城-南洋岸断裂 第四纪活动性 隐伏断裂 浅层地震勘探 盐城 

分 类 号：P315[天文地球—地震学] P313[天文地球—固体地球物理学]