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 is the most studied fault on Earth. Andrew Lawson, a geologist from the University of California, Berkeley, had named the fault after the San Andreas Lake (prior to the occurrence of the 1906 San Francisco earthquake) and later led an investigation into that event. The San Andreas Fault ruptured for a length of during the 1906 shock, both to the north of San Francisco and to the south in the Santa Cruz Mountains region. Several long term forecasts for a large shock along the San Andreas Fault in that area had been made public prior to 1989 (the event and