Three-dimensional magnetotelluric inversion based on unstructured hexahedral mesh edge-base finite element method
Structured hexahedral grids are not effective in simulating undulating terrain,and they unnecessarily encrypt the mesh extents.The Finite Element Method(FEM)is more flexible in the selection of the mesh for area segmentation,and can be used to divide the study area with an unstructured mesh,which is more suitable for the simulation of undulating terrain and complex geological formations.Therefore,based on the edge-base finite element algorithm,this paper adopts unstructured deformed hexahedral mesh to realize the three-dimensional magne-totelluric forward,which can not only simulate the terrain undulation better,but also encrypt the local key areas,reduce the number of mesh delineation of the expanding area,and alleviate the computational quantity.The correctness of the procedure is verified by forward simulation of the theoretical model.For the inversion,Gaussian-Newton algorithm was used to invert the theoretical models for flat,bimodal and bivariate terrains for trial calculations,comparing the differences in the results between the inversion with and without terrain,and finally the inversion of the impedance tensor data for the Kayabe area in Japan.Inversion results from theoretical models and measured data show that the algorithm in this paper can be used for three-dimensional magnetotelluric inversion.
万方数据
维普
