Axis anisotropic Occam's 3D inversion of tensor CSAMT in data space
Liu Xiao*, Zheng Fang-Wen
1. School of Hydraulic & Electric-power, Heilongjiang University, Harbin 150080, China.
2. School of hydraulic engineering, Nanchang Institute of Technology, Nanchang 330099, China.
Abstract：
As geological exploration conditions become increasingly complex, meeting the requirements of precise geological exploration necessitates the development of a controlled-source audio magnetotelluric (CSAMT) inversion method that considers anisotropy to improve the effectiveness of inversion accuracy and interpretation accuracy of data. This study is based on the 3D fi nite-diff erence forward modeling of axis anisotropy using the reciprocity theorem to calculate the Jacobian matrix by applying the search method to automatically search for the Lagrange operator. The aim is to establish inversion iteration equations to achieve the axis anisotropic Occam's 3D inversion of tensor CSAMT in data space. Further, we obtain an underground axis anisotropic 3D geoelectric model by inverting the impedance data of tensor CSAMT. Two synthetic data examples show that using the isotropic tensor CSAMT algorithm to directly invert data in anisotropic media can generate false anomalies, leading to incorrect geological interpretations. Meanwhile, the proposed anisotropic inversion algorithm can eff ectively improve the accuracy of data inversion in anisotropic media.Further, the inversion examples verify the eff ectiveness and stability of the algorithm.
2025, Vol. 22 
