宁河断裂伪随机震源地震勘探  

Pseudo-random source exploration for the Ninghe fault

作　　者：任政委[1] 郭淑君[1] 谢兴隆[1] 于蕾[1] REN Zheng-wei;GUO Shu-jun;XIE Xing-long;YU Lei(Centre for Hydrogeology and Environmental Geology,China Geological Survey,Baoding Hebei 071051,China)

机构地区：[1]中国地质调查局水文地质环境地质调查中心,河北保定071051

出　　处：《华北地质》2021年第1期56-60,共5页North China Geology

基　　金：中国地质调查局项目“黔中城市群综合地质调查(DD20190268)”。

摘　　要：宁河断裂位于天津市宁河区北部,断裂走向近东西,倾向南,全长约26 km,调查发现宁河断裂浅部存在一系列隐伏断裂带。第四系内部地层上更新统、中更新统、下更新统及第四系和第三系地质界面存在明显波阻抗差异,具备开展伪随机震源地震勘探的条件。经现场地震波速测试,第四系松散沉积地层地震纵波波速1300~1500 m/s,基岩波速超过2000 m/s。伪随机震源组合、实时噪声压制、F-K滤波3项关键技术,成功解决了高干扰环境下地震勘探难题。宁河断裂由5条正断层组成,断裂带近东西向平行展布。钻探揭示宁河断裂上断点已经断至上更新统内部,距地表66.9 m。The Ninghe Fault is located in the north of Ninghe District,Tianjin City..The fault runs nearly to the EW and tends to the south,with a total length of about 26 km.It is found that there are a series of concealed Fault zones in the shallow part of the Ninghe Fault.It is necessary to find out the spatial distribution characteristics of the shallow part of the Ninghe fault.There are obvious differences in wave impedance among upper Pleistocene,middle Pleistocene,lower Pleistocene in Quaternary internal strata and tertiary geological interfaces,which provides the prerequisites of pseudo-random seismic exploration.Pseudo-random source(wacker for short)can accurately,quickly and effectively detect the shallow strata structure,hidden fault structure spatial distribution characteristics.The field seismic wave velocity test was carried out.The seismic P-wave velocity of Quaternary unconsolidated sedimentary strata is 1300~1500 m/s.The wave velocity of bedrock exceeds 2000 m/s.The key techniques of pseudo-random source combination,real-time Noise suppression and F-K filtering have successfully solved the difficult problems of seismic exploration in high interference environment.The Ninghe Fault is composed of five normal faults,and the fault zone is parallel to the east-west direction.Drilling revealed that the upper break point of the Ninghe Fault had broken to the interior of the upper pleistocene,66.9 m from the surface.

关 键 词：伪随机震源 实时噪声 F-K滤波 

分 类 号：P631.4[天文地球—地质矿产勘探]