1868 Hayward earthquake
|Date||October 21, 1868|
|Countries or regions||United States, California|
The 1868 Hayward earthquake was the last large earthquake to occur on the Hayward Fault Zone in the San Francisco Bay Area, California, United States. It caused significant damage throughout the region, and was known as the "Great San Francisco Earthquake" prior to the 1906 San Francisco earthquake and fire.
The earthquake occurred at 7:53 a.m. on October 21, 1868. Its epicenter was likely located near Hayward, California, and its magnitude has been estimated to have been 6.8–7.0 on the Richter scale. At the surface, ground rupture was traced for 20 miles, from San Leandro to what is now the Warm Springs District in Fremont. The USGS estimates that Hayward experienced shaking measuring IX on the modified Mercalli scale. San Leandro experienced shaking measuring VIII, while San Francisco and Oakland experienced shaking measuring VII.
The town of Hayward experienced the most damage, with nearly every building destroyed or significantly damaged in the earthquake. The Alameda County Courthouse in San Leandro was destroyed, which resulted in the re-location of the County Seat to Oakland, its current site. The adobe chapel of Mission San José in what is now Fremont was also destroyed, as were several buildings in San Jose, San Francisco and throughout Alameda County. Damage was reported from Santa Rosa in the north to Gilroy and Santa Cruz in the south. Thirty deaths were attributed to the earthquake.
See also 
- "Historic Earthquakes: Hayward, California, 1868 October 21 15:53 UTC". United States Geological Survey. 1993. Archived from the original on 05 November 2008. Retrieved 2008-10-15.
- The 1868 Hayward Earthquake: 139 years and counting... (press conference). Hayward Area Historical and Society Museum: U.S. Geological Survey, Association of Bay Area Governments, Hayward Area Historical and Society Museum, Vice Mayor-City of Hayward. 17 October 2007. Retrieved 15 October 2008.