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ORIGINAL RESEARCH article

Front. Earth Sci.
Sec. Geomagnetism and Paleomagnetism
Volume 12 - 2024 | doi: 10.3389/feart.2024.1449515
This article is part of the Research Topic Geophysical Electromagnetic Exploration Theory, Technology and Application View all articles

Response characteristics of 3D tensor CSAMT in axis anisotropic media

Provisionally accepted
Xiao Liu Xiao Liu 1Shijie Gao Shijie Gao 2*
  • 1 Heilongjiang University, Harbin, China
  • 2 China Earthquake Administration, Beijing, Beijing Municipality, China

The final, formatted version of the article will be published soon.

    Considering the significant impact of anisotropy on forward and inversion results, this paper presents a research study on tensor controlled-source audio magnetotellurics (CSAMT) forward modeling in axis anisotropic media. In this study, the tensor resistivity of axis anisotropic medium is introduced according to the control equation of electric field with sources. The total electric field is decomposed into primary and secondary fields, with the primary field obtained using Key's algorithm and the secondary field calculated using the finite difference method. This approach enables three-dimensional (3D) modeling of tensor CSAMT in axis anisotropic media. The correctness of the algorithm is verified by comparing it with the results obtained using a two-dimensional (2D) finite element algorithm. Several sets of axis anisotropic 3D models are designed, and the response characteristics of anisotropic target bodies to plane waves and non-plane waves are summarized. The findings indicate that the Cagniard resistivity and tipper are sensitive to changes in the X and Y directions of the anomaly, but not sensitive to changes in resistivity in the Z direction. Additionally, in the near region, non-plane wave CSAMT signals may cause distortion in the Cagniard resistivity. The results highlight that tensor CSAMT has the capability to detect changes in resistivity in two-axis directions (X and Y), providing greater exploration advantages compared to scalar CSAMT. This study provides a foundation for the forward modeling and inversion of tensor CSAMT in arbitrary anisotropic media.

    Keywords: Tensor CSAMT, axis anisotropy, Cagniard resistivity, Tipper, forward algorithm

    Received: 15 Jun 2024; Accepted: 24 Sep 2024.

    Copyright: © 2024 Liu and Gao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Shijie Gao, China Earthquake Administration, Beijing, Beijing Municipality, China

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