S U M M A R YThe electrokinetic effect is one mechanism that causes the coupling between seismic and electromagnetic energies. This study deals with the numerical simulation of the electrokinetically induced coseismic electromagnetic fields associated with seismic waves created by a finite faulting in porous media. The key point of our numerical technique is to combine the point source stacking method with the Luco-Apsel-Chen generalized reflection and transmission method. After some validation test of our simulation method, we show several numerical simulation examples. Through a near-field model, we show that the point source approximation is not accurate in this configuration, as well as that the position of the rupture starting point and rupture speed obviously affect the coseismic EM fields. Then we numerically investigate the influence of different media properties on seismic waves and coseismic EM fields. We also carry out simulations of multilayer half-space models and show the characteristics of the coseismic EM fields. The preliminary results indicate that our numerical technique provides an effective approach of studying coseismic electromagnetic fields associated with seismic waves due to a finite faulting in porous media.

Chen's technique of computing synthetic seismograms, which decomposes every vector with a set of basis of orthogonality and completeness before applying the Luco-Apsel-Chen (LAC) generalized reflection and transmission coefficients method, is confirmed to be efficient in dealing with elastic waves in multi-layered media and accurate in any frequency range. In this article, we extend Chen's technique to the computation of coupled seismic and electromagnetic (EM) waves in layered porous media. Expanding the involved mechanical and electromagnetic fields by a set of scalar and vector wave-function basis, we obtain the fundamental equations which are subsequently solved by using a recently developed version of the LAC generalized reflection and transmission coefficients method. Our approach and corresponding program is validated by reciprocity tests. We also show a numerical example of a two-layer model with an explosion source. The P-to-EM conversion waves radiated from the interface may have potential application.

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