航空大地电磁响应特征分析及反演研究  

Analysis of response characteristics and research of inversion of airborne magnetotelluric

作　　者：李赓 曹飞翔 李万开 LI Geng;CAO Feixiang;LI Wankai(School of Physical and Electrical Engineering,Henan Polytechnic University,Jiaozuo 454150,China)

机构地区：[1]河南理工大学物理与电子信息学院,焦作454150

出　　处：《物探化探计算技术》2021年第2期224-231,共8页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：“十三五”国家重点研发计划重点专项(2017YFC0601806)。

摘　　要：航空大地电磁法以其机动灵活、效率高等优点,适用于在地势崎岖的偏远环境中开展快速普查作业。在航空大地电磁探测中,起伏地形会对倾子响应产生影响,另外由于倾子是无量纲传输函数,只包含电性结构的空间变化信息,而与电阻率的数值水平无关,单独利用倾子数据进行反演时,反演多解性更大。为解决上述问题,首先采用四边形网格模拟地形起伏;其次在倾子数据的反演目标函数中加入少量地面大地电磁数据拟合项,克服只拟合倾子的多解性缺陷;最后利用二维地电模型,验证本文有限元算法的正演精度,并分析起伏地形对倾子响应数据的影响。针对倾子数据缺乏背景电阻率信息这一问题,开展了带地形的倾子反演和倾子与地面大地电磁数据反演研究。研究结果表明:向倾子数据中加入少量地面大地电磁数据进行反演,可有效降低单独倾子反演对初始模型的依赖。With the advantages of flexibility and high efficiency,airborne magnetotelluric method is suitable for rapid reconnaissance in remote environments with rugged terrain.In airborne magnetotelluric exploration,an affective tipper response was conducted by the undulation terrain.In addition,tipper is a dimensionless transport function,which only contains the spatial change information of the electrical structure,and it has nothing to do with the numerical level of resistivity,and the inversion with the tipper data is more multi-solution.To solve the above problems,three processes were conducted in this paper.Firstly,the quadrilateral grid was used to simulate topographic relief in this paper.Secondly,a small number of ground magnetotelluric data fitting items were added into the inversion objective function of the tipper to overcome the defect of multi-solution of only fitting the tipper.Finally,the forward accuracy of the finite element algorithm in this paper was verified using the two-dimensional geoelectric model,and then the influence of undulating terrain on the response data of tipper is analyzed.The inversion of tipper data and inversion with tipper data and magnetotelluric data were carried out to solve the problem of the lack of background resistivity information on tipper data.The results show that a small number of magnetotelluric data was added to the inversion of the tipper,which can effectively reduce the dependence of the original model on the inversion of the tipper data.

关 键 词：航空大地电磁法 起伏地形 有限单元法 倾子 

分 类 号：P631.2[天文地球—地质矿产勘探]