大地电磁(MT)自适应有限元各向异性正演

电各向异性在自然界中普遍存在，特别是沉积盆地中的部分岩层经过压实变质作用，表现出很强的各向异性导电性，采用基于各向同性模型对实测资料进行正反演解释必然会造成困难甚至结果的错误，只有基于各向异性理论的正反演解释才更为合理准确。本文通过自适应有限元对大地电磁各向异性进行正演计算，分别模拟水平、垂直和倾斜各向异性介质在不同偏转角和主轴电阻率下的响应结果。结果表明：自适应有限元能够在后验误差的控制下得到合理的网格，使计算结果更加接近解析解；在各向异性介质中，大地电磁TE极化模式的视电阻率和阻抗相位与垂直于层面的电阻率无关；二维电各向异性结构中，大地电磁TM极化模式响应结果总是由主轴上的电阻率在y轴方向上的分量所决定。

Anisotropy Forward Modeling of Magnetotelluric(MT) Adaptive Finite Element

Electrical anisotropy is ubiquitous in nature, especially in some sedimentary basins, where some rock layers underwent compaction and metamorphism,showing a strong anisotropic conductivity,on which a positive and negative interpretation is more reasonable and accurate. The forward calculation of magnetotelluric anisotropy by adaptive finite element method was used to simulate the response of horizontal, vertical and oblique anisotropic media at different deflection angles and spindle resistivity in this study. The results show that the adaptive finite element can obtain a reasonable mesh under the control of the posterior error, and make the calculation result closer to the analytical solution; In anisotropic media, the apparent resistivity and impedance phase of the magnetotelluric TE polarization mode is independent of the resistivity perpendicular to the plane; In a two-dimensional anisotropic structure, the magnetotelluric TM polarization mode response is always determined by the resistivity component on the spindle in the y-axis direction.