2014 South Napa earthquake location. At least twelve aftershocks followed, including one of magnitude 3.9. The earthquake was the largest earthquake in the Bay Area since the magnitude 6.9 1989 Loma Prieta earthquake. Governor Jerry Brown declared a state of emergency due to the severe damage and the possibility of aftershocks. President Obama declared a major disaster for Napa and Solano counties. Several older commercial buildings in downtown Napa showed signs of extensive external damage even though many had been retrofitted for earthquake safety protection. The Goodman Library, Napa County Courthouse Plaza, Sam Kee Laundry Building, Downtown U.S. Post Office, Alexandria Hotel and Annex,
1989 Loma Prieta earthquake its aftershocks occurred within a recognized seismic gap) but the earthquake that transpired was not what had been anticipated. The 1989 Loma Prieta event originated on an undiscovered oblique-slip reverse fault that is located adjacent to the San Andreas Fault. Since many forecasts had been presented for the region near Loma Prieta, seismologists were not taken by surprise by the October 1989 event. Between 1910 and 1989 there were 20 widely varying forecasts that were announced, with some that were highly specific, covering multiple aspects of an event, while others were less complete and vague. With a M6.5 event on