This discrimination technique was applied to the earthquake catalogs of Northern Japan (1926–1960) and Southern California (1934–1960). Thirty percent of all events in the Japan catalog and 42 percent of events in the Southern California logs were identified as dependent events.
The statistical properties of the catalogs without dependent events were examined, in particular with respect to the Poisson process. Some small discrepancies with the Poisson process still existed using a decision threshold of s=0.02
Clusters of events were found that could not be related to any large magnitude main event.