Using P- and S-wave arrival times with the laterally varying P-wave velocity structure derived from analysis of a refraction survey of the Imperial Valley, a hypocenter is ascertained for the October 15, 1979, Imperial Valley earthquake: Latitude 32¿39.50' N, Longitude 115¿19.80' W, Depth 8.0 km, Time 23:16:54.40 GMT. |