NUMERICAL MODELING OF COUPLED SEISMIC AND ELECTROMAGNETIC WAVES IN FLUID-SATURATED POROUS MEDIA

PATRICIA M. GAUZELLINO; JUAN E. SANTOS; FABIO I. ZYSERMAN

MECANICA COMPUTACIONAL

AMCA

Año: 2007 vol. XXVI p. 1653 - 1672

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 derivedby 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 chosenelectromagnetic 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 boundaryconditions.The finite element procedure is carried out by using $C^0$ 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.