Date | January 9, 1857 |
---|---|
Duration | 1–3 minutes |
Magnitude | 7.9 Mw |
Depth | < 10 kilometers |
Epicenter | 35°42′N 120°18′W / 35.7°N 120.3°WCoordinates: 35°42′N 120°18′W / 35.7°N 120.3°W |
Fault | San Andreas Fault |
Type | Strike-slip |
Areas affected |
Central California Southern California United States |
Total damage | Severe |
Max. intensity | IX (Violent) |
Casualties | 2 killed |
The 1857 Fort Tejon earthquake occurred at about 8:20 am (Pacific time) on January 9 in central and Southern California. With an estimated moment magnitude of 7.9, it ruptured the southern part of the San Andreas Fault for a length of about 225 miles (350 kilometers), between Parkfield and Wrightwood. The earthquake was felt throughout much of California, as far north as the city of Marysville and as far south as the mouth of the Colorado River at the Gulf of California in Mexico, and as far east as Las Vegas, Nevada.
Though the shock was centered near Parkfield, the event is referred to as the Fort Tejon earthquake, because that was the location of the greatest damage. Fort Tejon is just north of the junction of the San Andreas and Garlock Faults, where the Tehachapi, San Emigdio, and Sierra Pelona Transverse Ranges come together.
The earthquake was the last large event to occur along that portion of the San Andreas Fault, and was estimated to have a maximum perceived intensity of IX (Violent) on the Modified Mercalli scale (MM) near Fort Tejon in the Tehachapi Mountains, and along the San Andreas Fault from Mil Potrero (near Pine Mountain Club) in the San Emigdio Mountains to Lake Hughes in the Sierra Pelona Mountains. Accounts of the events' effects varied widely, including the time of the main shock as well as foreshocks that occurred at several locations earlier in the morning.