| We simulate the magnetotelluric response to two-dimensional earth topographyusing finite elements. From Maxwell equations , we got the uniform equation fortransverse electric and transverse magnetic polarization using transmission surfaceequation which derived from transmission line equation of electrotechnics . Then ,weanalyse secondary field of two type polarizations and get individual boundaries.We directly compute total field and get finite elements equation by virtual workprinciple. In the program , we divide model into many rectangular meshes whichhave been subdivided into triangular ones. Linear interpolation of the total fieldparallel to strike over triangular elements allows accurate modeling of inclinedresistivity boundaries, including topographic surfaces. And writing codes isfacilitated by using rectangular meshes.The program is verified by comparison with the analytic response of asymmetrical layers model and with finite difference results (NLCG) of laterallyinhomogeneous model and topographic model.We discuss topographic effects in magnetotelluric surveys by two topographicmodels and confirm there lies in topographic effects in both transverse electric modeand transverse magnetic mode (especially the transverse magnetic mode).
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