基于多重网格算法的大地电磁三维反演研究  

Three-dimensional magnetotelluric inversion based on multigrid algorithm

作　　者：黄贤阳 殷长春[1] 苏扬 刘云鹤[1] 张博[1] 任秀艳[1] 李俊 燕帅 陈辉[2] HUANG XianYang;YIN ChangChun;SU Yang;LIU YunHe;ZHANG Bo;REN XiuYan;LI Jun;YAN Shuai;CHEN Hui(College of Geo-Exploration Science and Technology,Jilin University,Changchun 130026,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China)

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026 [2]东华理工大学核资源与环境省部共建国家重点实验室,南昌330013

出　　处：《地球物理学报》2024年第8期3150-3161,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42030806,42304149,42074120,42174167,42274093);江西省主要学科学术带头人培养计划项目(20204BCJL23058)联合资助。

摘　　要：为了推动大地电磁三维反演实用化的进程,本文融合了多重网格法(MG)与有限内存BFGS(L-BFGS)拟牛顿法,提出了一种高效的多尺度三维反演方法.该方法首先从细网格开始,逐步粗化生成最粗网格,然后从最粗网格开始反演,并逐级将粗网格反演结果为上一级细网格提供一个相对合理的初始模型,以加速细网格的反演迭代过程,并同时得到由粗到细的多尺度反演结果.本文首先测试了棋盘模型、起伏地层和侵入带模型,从理论上验证了该算法的高效性.结果表明,本文算法计算效率是传统反演的2~3倍.然后,利用该算法对美国Cascadia地区实测数据进行反演,进一步验证了该算法的实用性,结果显示该算法计算效率是传统反演的近2倍.期待本研究可为大地电磁三维反演问题提供一种高效、精确的解决方案.In order to promote the practical applications of three-dimensional(3D)Magnetotelluric(MT)inversion,we propose in this paper an efficient multi-scale 3D inversion algorithm by integrating the Multigrid(MG)with the Limited memory Broyden-Fletcher-Goldfarb-Shanno(L-BFGS)method.The method starts with a fine mesh and gradually coarsens to generate the coarsest mesh.Then the inversion is started from the coarsest mesh and the coarse inversion results are used step by step to provides a relatively reasonable initial model for the upper-level fine grids.This can accelerate the iterative process of inversion for fine meshes and obtain multi-scale inversion results from coarse to fine at the same time.In this paper,the chessboard model,and the undulating interface and intrusive zone models are first tested to theoretically verify the efficiency of the algorithm.The results show that the computational efficiency of this algorithm is 2~3 times that of traditional inversion.Then,the algorithm is used to invert the measured data in Cascadia area of the United State,to further verify the practicality of the algorithm.The results showed that the computational efficiency of the algorithm was nearly twice that of traditional inversion.Hope that this study will provide an efficient tool to 3D MT inversions.

关 键 词：大地电磁法 多重网格法 三维反演 多尺度 有限内存拟牛顿法 

分 类 号：P631[天文地球—地质矿产勘探]