DYNAMICAL SURFACE RESPONSE OF A SEMIINFINITE ANISOTROPIC ELASTIC MEDIUM TO AN IMPULSIVE FORCE

The dynamical surface response to an impulsive point source or line so urce at any location on the free surface of an anisotropic half-space is solved. The calculation of the Green's functions of the elastic hom ogeneous medium is based on the Cagniard-de Hoop method. This theoreti cal study models the generation-detection of transient surface acousti c waves with a point source-point receiver or with a line source-point receiver. An inspection of singular points in the complex plane of th e phase slownesses points out the striking phenomena due to anisotropy of surface wave propagation. As a result, the propagation of the Rayl eigh wave, of the surface skimming waves, and of the pseudosurface wav e are studied as well as the wavefronts focusing. In addition, the dif fraction effects by the cusps are emphasized. (C) 1998 Acoustical Soci ety of America.