隐伏活断层探测中的精定位技术——以银川盆地芦花台断裂为例  

THE ACCURATE LOCATION METHODS FOR BURIED ACTIVE FAULT EXPLORATION: AN EXAMPLE OF LUHUATAI FAULTS IN YINCHUAN GRABEN

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

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]宁夏回族自治区地震局,银川750001

出　　处：《地震地质》2015年第1期256-268,共13页Seismology and Geology

基　　金：中国地震局地震行业科研专项(201408023);中国地震局地质研究所基本科研业务专项(IGCEA1220);国家自然科学基金(41202158)共同资助

摘　　要：以银川盆地芦花台断裂为例,探讨隐伏活动断层精定位技术。经浅层地震勘探查明,芦花台断层总体走向NNE,倾向SEE,倾角73°-78°。根据取自钻孔的地层样品沉积年龄测定,又将主断层分为南段和北段。芦花台隐伏断层南段中更新世活动,而北段全新世活动。通过对浅层地震勘探断层上断点上延伸计算,使其与钻探得到的断层上断点埋深相匹配。通过断层的精确定位,得到了芦花台隐伏断层在浅表的几何分布、产状及活动性分段特征的认识。所得成果为石嘴山市城市辖区内的建设提供了重要参考依据。Based on the discussions on the basic ideas,methods and procedures for detecting buried faults and taking the example of Luhuatai buried faults in Yinchuan Basin,the paper introduces in detail the multi-means,multi-level detection methods for gradually determining the accurate location of faults.Multi-means refer to the technical methods such as shallow seismic exploration,composite drilling section,trenching,dating of sedimentary strata samples and calculation of upward continuation of fault＇s upper breakpoints,etc. Multi-levels refer to gradually determining accurate location of fault at different levels with the above means.Results of shallow seismic exploration reveal that the Luhuatai buried fault has a strike of NNE in general,dip SEE,with the dip angle between 73° to 78°. Geometrically,the fault consists of a main fault and a small north-segment fault in plane. The main fault runs along the NNE direction from Xixia District of Yinchuan City,passing through Jinshan Township to Chonggang Township,and there is a 4km or so intermittent zone between the main fault and the small north-segment fault. The small north-segment fault is 9km long,distributed between the north of Chonggang Township to the south of Shizuishan City. According to dating of sediments sampled from drill holes,the main fault can be further divided into the southern segment and the northern segment. The southern segment of Luhuatai buried fault is active in Pleistocene,while the northern segment is active in Holocene.Shallow seismic exploration can detect the upper breakpoint of fault deeper than drilling ortrenching does. If simply connecting the vertical projections of these breakpoints on the surface,there is a certain bias of fault strike. To this end,we did accurate location for the Holocene active northern segment of Luhuatai buried fault,in which upward continuation calculation is done based on the fault dip to match the upper breakpoint of fault obtained from shallow seismic exploration with the depth of the upper breakpoints obta

关 键 词：隐伏断层 浅层地震勘探 上断点 上延计算 精确定位 

分 类 号：P315.2[天文地球—地震学]