Date/Time:	January 9, 1857 about 8:20am PST
Magnitude	Mw 8.0 approximately
Location/Depth:	35.72N     120.32W
Descriptive location:	45 miles NE of San Luis Obispo
Faulting type:	right-lateral strike-slip
Faults involved:	San Andreas Fault
Length of surface rupture:	about 225 miles (360 km)
Maximum surface offset	about 30 ft (9 meters)

There is not a great deal of information about the Great 1857 Fort Tejon earthquake, but these links provide some information that is available about this event:

Summary (courtesy of SCEC)

Summary and Isoseismal Map (courtesy of NEIC)

The Great 1857 "Fort Tejon" Earthquake: Shake, Rattle, and Roll!
-from the Fort Tejon State Historic Park monthly newsletter

Noteworthy Foreshocks and Aftershocks & Isoseismal Maps

Eyewitness Accounts (from California Geology)

Bibliography of Selected Articles:

Agnew, D. and Sieh, K., 1978, A documentary study of the felt effects of the great California earthquake of 1857: Seismol. Soc. America Bull. 68, pp. 1717-1729.

Sieh, K., 1978, Central California foreshocks of the great 1857 earthquake: Seismol. Soc. America Bull. 68, pp. 1731-1749.

Sieh, K., 1978, Slip along the San Andreas Fault associated with the great 1857 earthquake: Seismol. Soc. America Bull. 68, pp. 1421-1428.

Meisling, K.E. and Sieh, K., 1980, Disturbance of trees by the 1857 Fort Tejon earthquake, California: J. Geophys. Res. 85, pp. 3225-3238.

Grant, L., and K. Sieh, 1993, Stratigraphic evidence for 7 meters of dextral slip on the San Andreas fault during the great 1857 earthquake in the Carrizo Plain: Seismol. Soc. America Bull. 83, 619-635.