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With the further development of the electromagnetic exploration technologies, the forward and inversion modeling of geophysical in three-dimensional numerical simulation fields is confronted with huge challenges. During the process of solving the partial differential equations, the methods of finite difference, finite element and volume element methods are usually adopted. For the complex topographic condition and geological structure, the conditions of the matrix formed finally will be very poor, seriously affecting the iterative and convergence rate in equation solution. In this paper, the algebraic multigrid preconditioned methods and conjugate gradient solution process are adopted to conduct parallel processing in combination of graphics processing unit (GPU), and the efficiency of DCs threedimensional forward modeling will be effectively improved.

In this paper, by comparing the basic equations and variational problem of two-dimensional magneto telluric (2DMT) method for symmetric anisotropic with isotropic bodies show the difference between the two cases in TE (Transverse Electric) and TM (Transverse Magnetic) modes. This paper adopts rectangular element subdivision and bilinear interpolation. The comparison results show that in TM mode the measuring point above the abnormal body can more effectively reflect the anisotropy effect than the one which is far away from the abnormal body. In addition, the results demonstrate that in TM mode the anisotropy effect cannot be ignored, and then in TE mode it is not sensitive to the anisotropy.

The workload of the 3D magnetotelluric forward modeling algorithm is so large that the traditional serial algorithm costs an extremely large compute time. However, the 3D forward modeling algorithm can process the data in the frequency domain, which is very suitable for parallel computation. With the advantage of MPI and based on an analysis of the flow of the 3D magnetotelluric serial forward algorithm, we suggest the idea of parallel computation and apply it. Three theoretical models are tested and the execution efficiency is compared in different situations. The results indicate that the parallel 3D forward modeling computation is correct and the efficiency is greatly improved. This method is suitable for large size geophysical computations.