Map

Where it struck, with the other significant earthquakes within 200 km. Circles are sized and colored by magnitude; select one for its page.

The earthquake

Date: December 8, 1812
Time: 15:00 UTC
Place: San Juan Capistrano, California, United States
Magnitude: 6.9 (ML)
Intensity: VIII, severe shaking, on the Modified Mercalli scale
Tsunami: None recorded
Epicenter: 34.370° N, 117.650° W
Country: United States
Region: North America and Hawaii
USGS record: The USGS’s page for this earthquake

The toll

Deaths: 40
Damage: Moderate (about $1 to $5 million)
Houses damaged: Few (about 1 to 50)

Where the literature gives no number, NCEI records a description on a scale of 1 to 4, printed here in its words. Damage is in millions of US dollars of the year of the event, not adjusted for inflation.

From Wikipedia

The 1812 San Juan Capistrano earthquake, also known simply as the Capistrano earthquake or the Wrightwood earthquake, occurred on December 8 at 15:00 UTC (07:00 a.m. local time) in Alta California. At the time, this was a colonial territory of the Spanish Empire. Damage occurred at several of the missions in the region of Pueblo de Los Ángeles, including Mission San Gabriel Arcángel and Mission San Juan Capistrano, where 40 parishioners were killed during the collapse of a church at an early morning service. Tree-ring and paleoseismic evidence show that there is a strong likelihood that the earthquake originated along the Mojave segment of the San Andreas Fault near Wrightwood, but other faults have been suggested as the cause.

Text from Wikipedia, “1812 San Juan Capistrano earthquake”, licensed CC BY-SA 4.0. Quoted as written, shortened to its opening; the full article has the rest.

Wikidata records: 40 deaths. These are counts entered by Wikidata’s editors; they may differ from the official count, and this page never adds them to another figure. Q4553974, CC0.

What happened

The USGS’s account of the effects of this earthquake.

The most severe loss occurred at the Missions of San Juan Capistrano and San Gabriel. The masonry church at Mission San Juan Capistrano 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 Mission San Buenaventura (Ventura). Walls of buildings were impaired at Mission San Fernando Rey, but no damage was reported at Missions San Diego or San Luis Rey.
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 Pallett 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 Mission San Buenaventura east to the San Bernardino Valley and south to San Diego. (Ref. 38, 56, 368, 521.)
Maximum observed Modified Mercalli Intensity (MMI) VIII

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.

This is one of the Largest Earthquakes in the United States (M>=7.0).

From the USGS event page for cdmg18121208150000000. U.S. Geological Survey text and figures are in the public domain.

Magnitude estimates

The magnitudes the USGS catalog lists for this earthquake, by scale and by who computed them. NCEI’s own scales are in the table above.

Mag.	Scale	Computed by	Notes
7.5	Mw, moment	CDMG	Preferred · Reviewed
6.9	ML, local (Richter)	USGS historic United States catalog	Final

References for the magnitude and location

The USGS’s notes on how this earthquake’s official magnitude and location were set.

Also known as The 1812 San Juan Capistrano Earthquake
Magnitude updated 18-Feb-2021
Reference:
California Department of Conservation, California Geological Survey
Downloadable list of magnitude 4 and greater earthquakes, compiled from various sources (1769-2000)
online at https://www.conservation.ca.gov/cgs/Pages/Earthquakes/earthquake-catalog.aspx

What the record says

NCEI’s account, from the sources it cites.

The earthquake was preceded by a weaker shock on December 8, which was felt from San Diego as far as the Franciscan Mission of Purisima, situated approximately at the site of the present city of Lompoc. At San Juan Capistrano, a church dome collapsed (largely due to the flimsiness of the structure); about 40 Indians, gathering for morning mass, were killed in the wreckage; other buildings at the mission were not damaged. At San Gabriel, the church cracked severely; the top of the building separated from the foundation; the icons fells from the altar and broke; most of the buildings at the mission were heavily damaged (Reference #415).

Sources NCEI cites

The publications NCEI lists for this record. The numbers match the “reference #” notes in its account above.

#542 Stover, Carl W., and Jerry L. Coffman (1993). Seismicity of the United States, 1568-1989 (Revised), U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington, D.C., 418 p.
#1128 Coffman, J.L. and C.A. von Hake (1973-1982). Earthquake History of the United States, Pub. 41-1, U.S. Department of Commerce, Boulder, CO, 1973, and 1982 Supplement.
#1171 Toppozada, T.R., C.R. Real, and D.L. Parke (1988). Toppozada, T.R., C.R. Real, and D.L. Parke, "Earthquake History of California," in Historical Seismograms and Earthquakes of the World (eds. W.H.K. Lee, H. Meyers, K. Shimazaki), Academic Press, Inc., San Diego, p. 267-275.
#415 Soloviev, S.L., and Ch.N. Go (1975). A catalogue of tsunamis on the eastern shore of the Pacific Ocean [dates include 1513-1968]. Academy of Sciences of the USSR, Nauka Publishing House, Moscow, 204 p. [Canadian Translation of Fisheries and Aquatic Sciences no. 5078, 1984, translation available from Canada Institute for Scientific and Technical Information, National Research Council, Ottawa, Ontario, Canada K1A OS2, 293 p.]
#13542 Wood, H.O., and Heck N.H., (1951). Earthquake History of the United States: Part II, Stronger Earthquakes of California and Western Nevada, Serial No. 609, Revised 1951 Edition. U.S. Department of Commerce, U.S. Coast and Geodetic Survey, Washington.
#13540 Pararas-Carayannis, George (2023). Earthquake and Tsunami Safety of Nuclear Power Plants – Case Study: The San Onofre Nuclear Plant in California, USA. vol. 42, no. 2, pages 109-145.

Other significant earthquakes nearby

Within 200 km, the deadliest first.

More

Significant earthquakes of 1812 The 1800s Recent earthquakes near here This day in weather history

Sources

Significant earthquakes from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-10-01. NCEI earthquake 1609. The written accounts and the magnitude estimates are from the USGS earthquake catalog, event cdmg18121208150000000, matched to this record by time, place and magnitude.