Seismic Waves Propagation Through Elastic Media with Prestressed Formation

Abstract

A basis for the development of numerical framework to modelling seismic wave propagation through prestressed zones is proposed. The governing equations for elastic waves in prestressed media written in stress-velocity formulation supplemented by the small rotation tensor equation are presented. The simplified version of equations is considered, assuming that the initial strain of prestressed state is small. The stress-induced anisotropy of unidirectionally compressed or stretched medium is studied. The rotated staggered grid technique is modified for solving formulated equations and the problem of interaction of the prestressed layer in a homogeneous half plane with elastic waves is solved as a two-dimensional numerical test problem. It is shown that the influence of this layer on the wave field can be significant. The existence of prestressed zones must be taken into account for forward modelling and inversion of seismic waves, especially in seismic travel-time tomography.