Abstract
A vertical seismic profile data set showing shear‐wave splitting from The Geysers, California, can be approximately fit with synthetic seismograms calculated with geometrical ray theory for anisotropic models of aligned cracks in the uppermost crust. Limited agreement between data and synthetics can be obtained if the cracks are constrained to be vertical, but a much better fit is possible if the cracks dip at an angle of 55 degrees.