Calaveras Fault 6.5 that occurred in 1911 in the Morgan Hill area. The most recent of these was a magnitude 6.2 earthquake near Morgan Hill in 1984. A magnitude 5.6 earthquake occurred on the Calaveras Fault on October 30, 2007 at 20:04 PDT (October 31, at 03:04 UTC), near Alum Rock. Prior to the 2014 South Napa earthquake, it was the most powerful quake to hit the Bay Area since the Loma Prieta earthquake of 1989, and the largest on the Calaveras Fault since 1984. Although it has been known for some time that the Calaveras and Hayward faults merge in the
1989 Loma Prieta earthquake oblique reverse faults and were within of the M6.9 Loma Prieta mainshock epicenter, near the intersection of the San Andreas and Sargent faults. Total displacement for these shocks was relatively small (approximately of strike-slip and substantially less reverse-slip) and although they occurred on separate faults and well before the mainshock, a group of seismologists considered these to be foreshocks due to their location in space and time relative to the main event. Each event's aftershock sequence and effect on stress drop was closely examined, and their study indicated that the shocks affected the mainshock's rupture process. Following the August 8,