A simple model to analytically assess the SH seismoelectric response of the vadose zone

FABIO I. ZYSERMAN; LEONARDO MONACHESI; LAURENCE JOUNIAUX

Paris

Congreso; Sixth Biot Conference on Poromechanics; 2017

Ecole de Ponts, Paris, IFSSTAR, CNRS

In this work an analytical solution of the seismoelectric conversions generated in thevadose zone, when this region is traversed by a pure SH wave, is derived. The considered model assumes a one-dimensional soil constituted by two homogeneous media incontact at the water table, and a shearing force located at the earth?s surface as the wavesource. The model also considers that the electroosmotic feedback can be neglected inBiot?s equations, as it is usually assumed. The upper medium represents a partially saturated porous rock whose porous space contains the minimum amount of water, whilethe lower medium is completely saturated with water, representing the saturated zone.The analytical expressions for both electric and magnetic fields are analyzed for a hypothetical scenario. The main result shows that a sharp contrast in water saturation atthe water table can induce strong interfacial responces in both fields.