October 1, 1865 Earthquake: Fort Humboldt, Eureka, California, United States
An earthquake struck Fort Humboldt, Eureka, California, United States on October 1, 1865 at 17:15:00 UTC.
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
- October 1, 1865
- Time
- 17:15:00 UTC
- Place
- Fort Humboldt, Eureka, California, United States
- Intensity
- IX, violent shaking, on the Modified Mercalli scale
- Tsunami
- None recorded
- Epicenter
- 41.000° N, 124.500° W
- Country
- United States
- Region
- North America and Hawaii
- USGS record
- The USGS’s page for this earthquake
The toll
- Damage
- Moderate (about $1 to $5 million)
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.
What happened
The USGS’s account of the effects of this earthquake.
Chimneys and brickwork were damaged at Eureka. At Fort Humboldt, south of Eureka on Humboldt Bay, all fort buildings were impaired, redwood trees were uprooted, and a fissure formed along the edge of the parade ground. (Ref. 38, 56, 368.)
Maximum observed Modified Mercalli Intensity (MMI) VII
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.
In addition, the quake was felt at Hydesville and Weaverville.
Abridged from Areas damaged by California earthquakes, 1900-1949, by T.R. Toppozada and D.L. Parke, California Division of Mines and Geology Open-File Report 82-17, Sacramento: 1982; updated and presented by interactive map on California Geological Survey website (http://maps.conservation.ca.gov/cgs/historicearthquakes/).
From the USGS event page for cdmg18651001171500000. 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 |
|---|---|---|---|
| 5.5 | ML, local (Richter) | CDMG | Preferred · Reviewed |
| 5.4 | 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.
Magnitude and Location updated 12-Aug-2019
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
Sources NCEI cites
The publications NCEI lists for this record. The numbers match the “reference #” notes in its account above.
- #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.
Other significant earthquakes nearby
Within 200 km, the deadliest first.
- December 20, 2022, Humboldt County, California, United States
- June 6, 1932, Eureka, California, United States
- December 21, 1954, Humboldt County, California, United States
- November 8, 1980, North Coast, California, United States
- December 26, 1994, Eureka, Samoa, Arcata, Blue Lake, California, United States
- March 20, 1855, Northern, California, United States
- January 10, 2010, Off Coast Northern, California, United States
- March 2, 1871, Humboldt County, California, United States
- April 25, 1992, Ferndale, Petrolia, Humboldt County, California, United States
- January 22, 1923, Northern, California, United States
- December 5, 2024, Offshore Cape Mendocino, California, United States
- January 31, 1922, Northern, California, United States
- February 9, 1941, Northern, California, United States
- August 17, 1991, Honeydew, Whitethorn, Petrolia, California, United States
- November 23, 1873, Northern, California, United States
More
Significant earthquakes of 1865The 1800sRecent earthquakes near hereThis 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 2098. The written accounts and the magnitude estimates are from the USGS earthquake catalog, event cdmg18651001171500000, matched to this record by time, place and magnitude.