NUMERICAL INVESTIGATION OF FRACTURE INTERFACE WAVES

Two-dimensional boundary element simulations are conducted to investig ate the properties of Rayleigh-type fracture interface waves generated by a line source located near a single fracture The fracture is model ed as a displacement-discontinuity boundary condition between two elas tic half-spaces with identical properties, Numerical simulations are p erformed for different fracture stiffnesses, source polarizations. and source depths. Symmetric and antisymmetric fracture interface waves a re observed with amplitudes and velocities that are controlled by the ratio of the fracture impedance to the half-space shear wave impedance . as predicted bq plane-wave theory [Gu et al., J. Geophys. Res. 101, 827-835 (1996); Pyrak-Nolte and Cook, Geophys. Res. Lett. 14, 1107-111 0 (1987)]. When the source is located off the fracture, these waves de velop at incidence angles that decrease with source depth.