The last known
surface rupture was less than 5,000 years ago. Recent research indicates that the San Cayetano fault may have been the source of the
December 21, 1812 earthquake.
Depending on location, the fault has an estimated slip rate between 1.3–9 millimeters (0.051–0.354 in). The recurrence rate between events is uncertain, but if the fault is associated with the 1812 event, it may be able to produce earthquakes approaching 6.5 – 7.3 in magnitude.