微动探测:地层分层和隐伏断裂构造探测的新方法

摘要

Microtremor survey as a new geophysical method has become an important technology for dividing strata,detection of basin structure,site selection of geothermal wells and survey of the buried fault structures and geological structures in mining area.The microtremor sounding method is used to detect geological interface with the distinct lithological differences in the error of the depth of about 5％,such as the lower boundary of the Cenozoic strata,the interface between Jurassic and Permian formations and the top interface of Permian to Carboniferous limestone,and so on.Fault fracture zone and buried fault structures are easy to be identified and interpreted with low velocity anomalies or obvious velocity differences in the apparent velocity profile of S-wave from microtremor survey.2D microtremor profiling technique has made better geological effects in the detection of buried geological structures (faults,collapse breccia pipes,etc.).This article describes the principles,methods and its applications.%微动探测作为地层分层和隐伏断裂构造探测的物探新方法,已成为盆地结构调查、地热井位选址和隐伏地质构造探测的重要物探手段.微动测深确定岩性差异较大的地质界面,如新生界地层底界、侏罗系与二叠系地层分界面、二叠系-石炭系灰岩顶界面等,深度误差可控制在5％左右.断层破碎带/隐伏断裂构造在微动视S波速度剖面上显示为低速异常或明显的速度差异,易于识别、解释.二维微动剖面技术已在探测隐伏地质构造(断层、陷落柱等)方面取得较好地质效果.本文介绍其原理、方法和应用实例.