MT等效视电阻率法在构建电性柱结构模型中的应用  

The application of the MT equivalent apparent resistivity method to the construction of electrical column structure

作　　者：仇根根[1] 张小博[1] 方慧[1] 钟清[1] 裴发根[1] 袁永真[1] 杜炳瑞 

机构地区：[1]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000

出　　处：《物探与化探》2014年第4期732-736,共5页Geophysical and Geochemical Exploration

基　　金：国家深部探测专项(SinoProbe-01-04)

摘　　要：电性柱结构模型通常用来代表某一地区范围内在纵向上的电性变化特征。利用大地电磁测深资料进行区域电性特征分析时,一般采用单独的TE模式、TM模式、TETM均值模式进行一维反演计算,难以取得较好的区域电性特征。等效视电阻率法是依据阻抗张量复数旋转不变而推导出来的,计算测点下方等效视电阻率的一种计算方法,计算结果不会因地表测量方位不同而发生变化。在地质条件非常复杂地区,利用该方法可以较好地获得该地区具有代表性的纵向电性结构特征。以东北阵列大地电磁"标准点"为例,依据实测资料设计一个复杂的三维模型,通过模型的正反演计算和模型对比实验研究,该方法在横向上、纵向上均具有较好的分辨率;将该方法应用到东北阵列大地电磁场"标准点"电性柱模型构建上,取得了较好的应用效果。The electrical column structure model is usually used to represent the longitudinal variation of electrical characteristics within a region. When we analyze the overall electrical characteristics by regional MT sounding data,it is difficult to get satisfactory regional electric characteristics through one-dimensional inversion by using single TE,TM,and mean of TE with TM data conventionally. The equivalent apparent resistivity method is used to calculate equivalent apparent resistivity below the station based on the impedance tensor plural rotate invariantly. The calculation result is not dependent on the change of surface measuring azimuth. In areas with very complex geological conditions,the use of equivalent apparent resistivity method can obtain the longitudinal electrical structure of the region. Taking northeast MT array ＂ standard station＂ as an example,the authors designed a very complex three-dimensional model according to the measured data. Studies show that the equivalent apparent resistivity method has better resolution in the transverse direction and the longitudinal direction,as shown by model forward and inversion calculation and comparison experiments. The authors applied the method to the construction of electrical column structure at the northeast MT array standard station and achieved a good application effect.

关 键 词：大地电磁 旋转不变量 等效视电阻率 电性柱模型 一维反演 

分 类 号：P631.3[天文地球—地质矿产勘探]