Source parameters of the June 29, 1992 Little Skull Mountain Earthquake from complete regional waveforms at a single station

The June 29, 1992, m b =5.5, Little Skull Mountain earthquake occurred 20 km southeast of Yucca Mountain within the boundaries of the Nevada Test Site. This event was recorded at a very broadband station located about 310 km to the east at Kanab, Utah. Both body and surface waves from this single station were used in a grid search technique for the best fitting double couple moment tensor. The technique minimizes the misfit between reflectivity generated complete synthetic seismograms and the three‐component displacement data via a search over the strike, dip and rake of the source. In the passband of 50–15 s period, the grid search results in a well defined, nearly pure normal mechanism with a strike of 35°, a dip of 54°, a rake of −87°, and a seismic moment of 4.1 × 10 17 N‐m. Applying the same technique to the large aftershock on July 5, 1992 we obtain a somewhat less well defined minimum with a strike of 358°, a dip of 36°, a rake of −177°, and a moment of 4.3 × 10 15 N‐m. The minimum‐compression axes of these mechanisms are consistent with northwest‐southeast extension in the Basin and Range.