上海张堰-金山卫隐伏活动断层活动特征及综合地球物理证据  

The activity characteristics and comprehensive geophysical evidence of the Zhangyan –Jinshanweiconcealed active fault in Shanghai, China

作　　者：宋春华 郁飞 施刚 SONG Chunhua;YU Fei;SHI Gang(Shanghai Geotechnical Engineering&Geology Institute Co.,Ltd,Shanghai 200072,China;Shanghai Geological Engineering Exploration(Group)Co.,Ltd,Shanghai 200072,China)

机构地区：[1]上海市岩土地质研究院有限公司,上海200072 [2]上海市地矿工程勘察(集团)有限公司,上海200072

出　　处：《地质力学学报》2023年第6期888-897,共10页Journal of Geomechanics

基　　金：上海市财政资金项目(18-29780)。

摘　　要：上海城市隐伏断层十分发育,第四纪以来沉积了数百米厚的松散沉积层,受限于其特大城市复杂高干扰环境背景,隐伏断层的探测与活动性特征研究难以取得理想的效果,城市地质安全面临严重风险。文章通过高精度重力面积测量、高分辨率浅层地震勘探等地球物理探测方法,结合周边钻孔地层分层、地应力和年代学测试分析(碳十四和光释光),对张堰-金山卫断层第四纪和现今的活动性开展了探测与研究。结果显示,该断层空间上具有较好的延展性,断层行迹在布格重力异常和地震时间剖面上均有较好的地球物理证据反映。研究认为张堰-金山卫断层为逆冲断层,同时具有继承性和新生性活动特征,总体走向为北西向315°,倾向南西,基岩面断距约10 m,上断点已错断至第四系中更新统内,最新活动时代为中更新世,目前北西向地应力状态易于发生张扭性活动,该断层现今活动性依然需持续关注。此次研究探测思路与成果可为类似城市开展隐伏活动断层探测及活动性分析提供借鉴和参考。The concealed faults in the urban area of Shanghai are well-developed,accumulating several hundred meters of loose sediment layers since the Quaternary.Hindered by the complex and highly disturbed urban environment,the detection and characterization of concealed faults face challenges,posing significant geological risks for urban safety.This study employs high-precision gravity area measurements,high-resolution shallow seismic exploration,and geophysical exploration methods.It integrates geological stratification from surrounding boreholes,stress,and chronostratigraphy analyses(C14 and optically stimulated luminescence)to investigate the Quaternary and current activity of the Zhangyan–Jinshanwei fault.Results show that the fault exhibits good spatial continuity,with evidence reflected in Bouguer gravity anomalies and seismic time profiles.The Zhangyan–Jinshanwei fault is identified as a thrust fault with inherited and newly developed activity characteristics.Its overall trend is northwestward at 315°,dipping southwest,with a fault distance of approximately 10 meters along the bedrock surface.The upper fault point has been displaced to the mid-Pleistocene in the Quaternary.The most recent active period occurred during the mid-Pleistocene,and the current northwestward stress state makes the fault susceptible to extensional and torsional activities.Continuous attention is required for the ongoing activity of this fault.This study's detection approach and findings can serve as a reference for similar urban concealed active fault detection and activity analysis.

关 键 词：隐伏活动断层 张堰-金山卫断层 高精度重力面积测量 高分辨率浅层地震勘探 年代学 地应力 

分 类 号：P631.4[天文地球—地质矿产勘探]