音频大地电磁法对隐伏构造的识别与应用——以河南省郑州市老鸦陈周边为例  

Identification and application of audio magnetotellurics to the hidden structure:A case study of Laoyachen in Zhengzhou,Henan Province

作　　者：康敏[1] 康健 秦建增[1] 

机构地区：[1]中国地震局地球物理勘探中心,河南郑州450002 [2]中国石油青海油田分公司勘探开发研究院,甘肃敦煌736202

出　　处：《物探与化探》2018年第1期61-67,共7页Geophysical and Geochemical Exploration

基　　金：中国地震局地震科技星火计划项目(XH16051Y);中国地震局地球物理勘探中心青年基金项目(YFGEC2016009)

摘　　要：为探明郑州市及其周边地区隐伏构造的分布情况,在郑州北郊老鸦陈断层东侧布设了一条EW向音频大地电磁(AMT)测线,并对野外数据进行了去噪、主轴旋转、阻抗分析、静态校正等处理。用正则化反演理论方法——非线性共轭梯度法(NLCG)进行二维反演,利用与AMT测线接近平行的地震剖面分层结果对模型进行约束反演,降低了反演的多解性以及NLCG对初始模型的依赖性,最终取得了较好的电性结果。结果表明测线下方分为3层,并有一隐伏构造。结合地质、地球物理资料推断解释,此隐伏构造有可能是一条发育在晚新近系的正断层,亦或为第四系地层与新近系地层的不整合接触面。本文的研究工作为进一步探明城市隐伏构造提供了地球物理及技术手段依据。In order to prevent geological disasters and improve urban planning, it is of great significance to explore the distribution of hidden structures in Zhenzhou and its surrounding areas by audio magnetotellurics （AMT）. In this paper, an EW-trending AMT profile was set up on the east of Laoyachen fauh in the northern suburb of Zhenzhou. Noise reduction, rotation, impedance analysis and static correction of the original data were processed. The 2D regularization inversion theory method, i.e., nonlinear conjugate gradient method （NLCG） was used. The initial mode was constrained by seismic layering results, which was nearly in parallel with the AMT profile, which reduced the multiple solution and the NLCG＇s dependence on the initial mode. Good electrical results were obtained, which show that there are three layers and a hidden structure in the profile. At the same time, combined with geological and geophysical data, the authors inferred the explanation. It is inferred that the hidden structure may be a normal fault developed in Late Neogene or an uncon- formable contact surface between Quaternary and Neogene strata. The results obtained by the authors provide the geophysical and tech- nical basis for further exploration of urban hidden structure.

关 键 词：音频大地电磁法 电性分层 分层模型约束 隐伏构造 

分 类 号：P631[天文地球—地质矿产勘探]