ABSTRACT
One of the most characteristic features of rocks is occurrence of cracks of different kind and size. This discontinuities have an important influence on physical properties of rocks. Preferred orientation of crack systems involves anisotropy of seismic wave velocity and anisotropy of rock resistivity. Cracks cause velocity reduction, which depends on crack geometry and elastic properties of material filling cracks (water, gas or silt). The flow of cracks on electric conductivity of rock is different. Depending on crack filling they can enlarge or reduce electric resistivity in comparison to uncracked solid. The study of relationships between crack and seismic or electric anisotropy allowed to use combined geophysical methods like seismic refraction method and multi-level electric profiling for determination of fracture density and orientation of crack systems and fracture filling as well. Earlier measurements were done for rocks without overburden (Idziak, Stan-Kleczek, 2006b).
