Abstract
Oriented cracks and/or oriented joints in rocks produce anisotropic elasticity. When the rock has anisotropic elasticity, one must know more than two elastic constants to describe fully the elastic behavior of rocks under stress. In an anisotropic body, there are twenty-one elastic constants with respect to an arbitrary coordinate system. When a material has some sort of symmetry, a number of non-zero elements, with respect to the symmetry axes, can be reduced. In general, the full information of elastic symmetry has to be known, because the elastic constants of rock-forming minerals and rocks are determined by measuring elastic properties with respect to the elastic symmetry. In this study, it was tried to determine twenty-one elastic constants of anisotropic rocks, and to find symmetry axes of the rock, by using elastic wave velocities propagating in various directions. The calculated elastic constants and the axes of symmetry of Oshima granite agreed well with the published results which were determined in the assumption of orthorhombic elasticity with respect to the planes of oriented cracks.
