Assessment of creep events as potential earthquake precursors: Applicationto the creeping section of the San Andreas Fault, California

We report the analysis of over 16 years of fault creep and seismicity data from part of the creeping section of the San Andreas fault to examine and a ssess the temporal association between creep events and subsequent earthqua kes. The goal is to make a long-term evaluation of creep events as a potent ial earthquake precursor. We constructed a catalog of creep events from ava ilable digital creepmeter data and compared it to a declustered seismicity catalog for the area between San Juan Bautista and San Benito, California, for 1980 to 1996. For magnitude thresholds of 3.8 and above and time window s of 5 to 10 days, we find relatively high success rates (40% to 55% 'hits' ) but also very high false alarm rates (generally above 90%). These success rates are statistically significant (0.0007 < P < 0.04). We also tested th e actual creep event catalog against two different types of synthetic seism icity catalogs, and found that creep events are followed closely in time by earthquakes from the real catalog far more frequently than the average for the synthetic catalogs, generally by more than two standard deviations. We find no identifiable spatial pattern between the creep events and earthqua kes that are hit or missed. We conclude that there is a significant tempora l correlation between creep events and subsequent small to moderate earthqu akes, however that additional information (such as from other potential pre cursory phenomena) is required to reduce the false alarm rate to an accepta ble level.