A 600-m borehole vertical seismic profiling (VSP) survey conducted in crystalline rock in the Mojave Block stress province, southern California, yielded 100 oriented three-component seismograms from a fan-shooting geometry with radius of 100 m using both vertical and horizontal vibrators and a vertical impact source. The seismograms show up to 12 ms of shear wave splitting and 5% lateral velocity heterogeneity. First- and second-order ray tracing wave used to model the travel times times and amplitudes of P-, SV- and SH- waves in a three-dimensional mildly heterogeneous medium with elastic anisotropy induced by aligned fractures. A least squares inverse procedure was used to improve model parameters determined by forward modeling; the final root mean square travel time residual was ¿2 ms. For purposes of amplitude computation we assume that the wavelets observed in a VSP section derive from a smooth intermediate interface (base of weathering layer of sedimentary/basement interface) that is illuminated by a narrow range of ray angles originating at a point source on the surface. Source-derived amplitude complications are thus minimized. Our results strongly indicate a population of vertical cracks with an average crack density of 0.035 oriented in the N31.5¿W direction. Such a fracture population is consistent with regional principal strain and stress determinations. Ray series geometric amplitudes were consistent with the observation that wave motion parallel to the aligned fractures decayed more slowly than wave motion transverse to the aligned fractures. We estimated that Q≥75--100; we were unable to measure a polarization-dependent Q. ¿American Geophysical Union 1990