Historic Earthquakes

Southwest of San Bernadino County, California
1812 December 08 15:00 UTC
Magnitude 6.9

The most severe loss occurred at the Missions of San Juan Capistrano and San Gabriel. The masonry church at San Juan Capistrano Mission was destroyed, killing 40 people attending services. Other buildings at the mission were left "in bad condition." The church at San Gabriel also sustained much damage, and many cracks formed in the bell tower. The upper part of the tower later fell, as did the weathervane. The living quarters of the ministers and offices of the mission also were damaged extensively. Three tremors described as "horrible" probably caused damage at San Buenaventura Mission (Ventura). Walls of buildings were impaired at Mission San Fernando Ray, but no damage was reported at San Diego or San Luis Rey Missions.

This earthquake may have ruptured the San Andreas fault at Wrightwood. The rupture may have extended at least 25 km to the northwest, where it is preserved in the peat bog at Pallet Creek. The fault rupture at Pallet Creek is comparable to that formed by the 1857 earthquake in the southern Coast Ranges. The main earthquake was felt from San Buenaventura Mission west to San Bernardino Valley and south to San Diego.

Abridged from Seismicity of the United States, 1568-1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.