Date June 1838 (1838-06) Epicenter (approximate) | Magnitude 6.8–7.2 Mw Casualties Unknown | |
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Areas affected San Francisco Bay AreaNorthern CaliforniaUnited States | ||
The 1838 San Andreas earthquake is believed to be a rupture along the northern part of the San Andreas Fault in June 1838. It affected approximately 100 km (62 miles) of the fault, from the San Francisco Peninsula to the Santa Cruz Mountains. It was a strong earthquake, with an estimated moment magnitude of 6.8 to 7.2, making it one of the largest known earthquakes in California. The region was lightly populated at the time, although structural damage was reported in San Francisco, Oakland, and Monterey. It is unknown whether there were fatalities. Based on geological sampling, the fault created approximately 1.5 meters (3.3 feet) of slip.
For years, another large earthquake was said to have occurred two years earlier in June 1836 along the Hayward fault, however this is now believed to be referring to the 1838 San Andreas earthquake. There is no evidence a large earthquake hit the region in 1836.