SKS SPLITTING BENEATH SOUTHERN CALIFORNIA



Measurements of SKS phase splitting were obtained from nineteen seismic stations in southern California. The fast polarization directions are 53 degrees at the southern end of the Great Valley, 82 +-8 degrees in the western Transverse Ranges and northern Peninsular Ranges, 95 +- 4 degrees in Mojave Desert, and 70 degrees on San Clemente Island. The splitting time ranges from 0.8 to 1.8 seconds, which is consistent with an anisotropic layer of 100 to 200 km thick for 4% anisotropy.