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

LEONARDO MONACHESI; ZYSERMAN, FABIO IVÁN; LAURENCE JOUNIAUX

Paris

Congreso; 6th Biot Conference on Poromechanics - A tribute to Olivier Coussy; 2017

Ecole des Ponts ParisTech

In this work an analytical solution of the seismoelectric conversions generated in the vadose 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 in contact at the water table, and a shearing force located at the earth´s surface as the wave source. The model also considers that the electroosmotic feedback can be neglected in Biot´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, while the 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 at the water table can induce strong interfacial responces in both fields.