Stable Calculation of Responses for a Plane Electromagnetic Wave in an Anisotropic Layered Media for the Modeling of Magnetotelluric Data

Hee June Lee; Janghwan Uhm; Junyeong Heo; Dong-Joo Min

doi:10.32390/ksmer.2024.61.4.284

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2024 Vol.61, Issue 4 Preview Page Next Page

Research Paper

Stable Calculation of Responses for a Plane Electromagnetic Wave in an Anisotropic Layered Media for the Modeling of Magnetotelluric Data 이방성 층서에서의 자기지전류 탐사 자료 모델링을 위한 평면 전자기파에 대한 반응 계산 안정화

31 August 2024. pp. 284-295

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Abstract

Research in multi-dimensional magnetotelluric (MT) modeling and inversion, particularly within anisotropic media, is gaining substantial interest. One-dimensional (1-D) modeling is utilized as boundary conditions necessary for accurate 2-D or 3-D anisotropic modeling. Based on Maxwell’s equations and interface boundary conditions, we developed a new algorithm to calculate electromagfor both 1-D isotropic and anisotropic layered models. However, this algorithm encounters stability issues at considerable depths or within exceptionally thick layers. To address these challenges, we introduced two stabilization strategies. The first strategy alters the exponential terms in the plane-wave solutions to mitigate instabilities, while the second evaluates each layer’s contribution to numerical instability, replacing problematic thick layers with an infinite half-space. Through numerical tests on a four-layer anisotropic model, these strategies proved effective, ensuring stable computations of electromagnetic fields at any depth and in configurations with thick layers, thereby enhancing the model’s applicability for in-depth anisotropic analyses.

Keywords

magnetotelluric

1-D anisotropic layered model

stabilization strategies

electromagnetic fields

modeling

본 연구에서는 자기지전류(Magnetotelluric, MT) 탐사 자료 모델링을 위한 1차원 이방성 매질에서의 평면파 반응 계산의 안정화 전략을 제안한다. 층서구조에 대한 반응, 2차원이나 3차원 모델링에서 경계조건으로 이용되기 때문에, 이방성 매질에 대한 고차원 모델링의 정확한 해를 구하기 위해서는 이방성 층서 구조에 대한 정확하고 안정적인 해의 계산이 필수적이다. 고심도 혹은 매우 두꺼운 층들이 존재할 때 이방성 층서 구조 해의 불안정성 문제를 극복하기 위해 두 가지 안정화 전략을 제안한다. 즉, 평면파 해의 지수 항을 수식적으로 깊이가 증가함에 따른 발산 현상을 방지하거나, 층서 모델에서 불안정성을 일으키는 두꺼운 층이 존재할 때 이 층을 반무한 매질으로 치환해 수치적 안정성을 향상시킨다. 두 안정화 전략은 임의의 깊이와 두꺼운 층이 존재하는 경우에도 안정적으로 전자기장 성분들을 구할 수 있어, 제안된 알고리즘은 이방성 층서 구조의 임의의 깊이에서 1차원 해를 계산할 때 활용될 수 있을 것으로 기대된다.

키워드

자기지전류

1-D 이방성 층서 구조

안정화 전략

전자기장

모델링

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Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society of Mineral and Energy Resources Engineers
Journal Title(Ko) :한국자원공학회지
Volume : 61
No :4
Pages :284-295
Received Date : 2024-05-17
Revised Date : 2024-06-28
Accepted Date : 2024-07-01
DOI :https://doi.org/10.32390/ksmer.2024.61.4.284

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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