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Abstract

Electromagnetic methods in the time domain have been widely used in geophysical exploration, and their application in complex media increases the necessity for better forward and inverse modeling. Furthermore, electromagnetic modeling is fundamental in fieldwork design, processing, and inversion. Therefore, we must create more extensive and complex earth models and use more sophisticated numerical algorithms.This ongoing research project explores the Spectral Element Method (SEM) to model the three-dimensional transient electromagnetic fields on isotropic and anisotropic media. We use an explicit time-stepping method based on finite differences.The principal feature of SEM is that it uses high-order basis functions. We use up to an eight-order basis in our experiments for different scenarios. In addition, we compare our numerical solutions with analytical solutions for a whole space using a vertical and horizontal electric dipole as a source in a turn-off and turn-on stage.Finally, we found that higher-order polynomial basis functions and coarse meshes provided better results than a finer mesh with first-order polynomials. The 2nd and 4th-order bases yield accurate results without significantly increasing computational costs.