大地电磁倾子资料的三维正演研究  

Research on the 3D magnetotelluric tipper forward modeling

作　　者：邓居智[1] 蓝泽鸾[1] 陈辉[1] 周峰[1] 

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,南昌330013

出　　处：《地球物理学进展》2015年第4期1666-1672,共7页Progress in Geophysics

基　　金：国家自然科学基金(41164003;41404057);国家科技支撑计划(2011BAB04B03);东华理工大学研究生创新基金(DYCA13026);江西省研究生创新基金(YC2013-S177)联合资助

摘　　要：在实际复杂的三维地电条件下,倾子作为大地电磁法的重要解释参数之一,其正演模拟和响应分析对提高大地电磁法的探测精度具有重要作用.本文在简要阐述大地电磁三维正演基本理论的基础上,利用交错网格有限差分法开展了大地电磁三维倾子正演模拟研究,首先正演模拟单个低、高阻两种地电模型的倾子响应,结果表明倾子资料能够较好反映地下异常体的空间分布;在此基础上,设计了含有两个低(高)阻异常体和低阻垂直断层的复杂组合模型并计算了其三维倾子响应,结果表明,倾子具有对复杂的地电结构良好的空间分辨率,且倾子响应既保留了模型中每单个异常体的倾子响应形态,又表现出了异常体之间相互作用的整体响应情况,进一步加深了对倾子的响应特征和规律、以及倾子资料对异常体边界的识别能力的认识,为倾子资料从定性解释向定量解释发展提供参考和依据.Under the actual complex condition of 3Dgeoelectric structure,tipper,as one of the important parameters of magnetotelluric method,plays an important role in improving the detection accuracy of magnetotelluric method via its forward modeling and response analysis. On the basis of briefly expounds the basic theory of magnetotelluric 3Dforward,this paper applied the staggered-grid finite difference method to carry out the 3D magnetotelluric tipper forward modeling.Firstly,we calculated calculated the tipper responses of two earth-electricity model which contains only low resistivity or high resistivity abnormal body,respectively,whose results show that tipper data can better reflect the spatial distribution of the underground abnormal body,then on which basis designed a complex combination model containing two low（high）resistivity abnormal bodies and conductive vertical fault and calculate their 3Dtipper responses,which show that their tipper responses are obvious that both retain each single abnormal body＇s response form and show up the whole response feature of interactions between the abnormal body,by which we further recognize the response features and rules of tipper, as well as its recognizability to abnormal body boundary,that eventually to provide reference and basis for the development of tipper from qualitative interpretation to quantitative interpretation.

关 键 词：大地电磁测深 倾子 正演模拟 交错网格有限差分法 

分 类 号：P631[天文地球—地质矿产勘探] P318[天文地球—地质学]