Waveform Relocated Earthquake Catalog for Southern California ( 1981 to June 2011 )

We determine a new relocated catalog, HYS_catalog_2011, for southern California from 1981 through June 2011. About 75.3% of the hypocenters are calculated with absolute and differential travel-time picks, and 24.7% could be relocated only by using absolute travel-time picks with 3D or 1D velocity models. The total catalog consists of more than 502,000 earthquakes in the region extending from Baja California in the south to Coalinga and Owens Valley in the north. The catalog consists of three M 7.1, M 7.2, and M 7.3 mainshocks; their foreshocks and aftershocks; and background seismicity caused by tectonic and other processes in the southern California crust. Hypocenters in the new relocated catalog exhibit tighter spatial clustering of seismicity than does the routinely generated catalog, and the depth distribution is tighter and reflects the thickness of the seismogenic zone more accurately. Compared to the standard catalog, the relocated hypocenters are more easily related to other data sets, such as mapped late Quaternary faults.