Stress Dependent Elasticity of Porous and Fractured Rocks

H040 Z-99 STRESS DEPENDENT ELASTICITY OF POROUS AND FRACTURED ROCKS SERGE A. SHAPIRO and AXEL KASELOW FR Geophysik Freie Universität Berlin Malteser Str. 74-100 12249 Berlin Germany Summary Elastic properties of rocks are functions of tectonic stresses. Using the theory of poroelasticity we analyze mechanisms of these dependencies related to changes of the rock-pore-space geometry. We develop a formalism describing elastic moduli and anisotropy of rocks as non-linear functions of confining stresses and pore pressure. In a first approximation elastic moduli seismic velocities as well as the porosity depend on the differential stress i.e. the difference between the confining tectonic