Numerical Modeling Of Coupled Seismic And Electromagneticwaves In Fluid-Saturated Porous Media

Abstract

This work presents a finite element procedure for the numerical approximation of the electroseismic
problem at seismic frequencies. The electroseismic equations used are the ones derived by S.
Pride, consisting in the coupled Biot’s equations of motion and Maxwell’s equations where the seismoelectric
feedback is being neglected. The modeled domain comprises two half-spaces, one being air, and
the other one a horizontally layered medium. The chosen electromagnetic source is an infinite plane of
time dependent electric current located above the surface of the Earth. Under these two assumptions, the
electric and magnetic fields and the solid and fluid displacements depend only on one coordinate, namely
the one chosen to describe the vertical variations of the Earth; therefore the problem can be considered
to be one dimensional.
The existence of a unique solution for both the continuous and discrete weak problems is analyzed, considering
a finite computational domain by recoursing to absorbing boundary conditions.
The finite element procedure is carried out by using C0 linear functions for the electric field and the
solid displacements, and piecewise constant functions for the magnetic field and fluid displacements,
respectively. A synthetic example showing the capabilities of the numerical method is presented.