August 1, 1975 Earthquake: Oroville, California, United States
A magnitude 5.6 earthquake struck Oroville, California, United States on August 1, 1975 at 20:20:12 UTC, 15 km below the surface.
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
- August 1, 1975
- Time
- 20:20:12 UTC
- Place
- Oroville, California, United States
- Magnitude
- 5.6 (Ms)
- Focal depth
- 15 km (9 mi)
- Intensity
- 8 on the Modified Mercalli scale
- Tsunami
- None recorded
- Epicenter
- 39.439° N, 121.528° W
- Country
- United States
The toll
- Injuries
- 10
- Damage
- $3 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 the record says
NCEI’s account, from the sources it cites.
1975. Aug. 1, 20 20 UTC. Near Oroville, Butte
County, Calif., intensity VIII. Structural damage, consisting mainly of cracks in chimneys and walls, broken windows and plaster, and loosened light fixtures, occurred at several schools, hospitals, and houses in the Oroville-
Thermalito area. Many chimneys toppled or had to be taken down in Oroville and Palermo. Property damage was estimated at $2.5 million. This earthquake was associated with the first recorded surface faulting in the western foothills of the Sierra Nevada. New fractures in the ground were observed in a 3.8-km-long north- to north-northwest-trending zone. The block east of the fault moved upward relative to that on the west, as shown by about 55 mm of slip across the surface ruptures and 180 mm of vertical movement of benchmarks near the rupture zone. Felt over a large area of northern California and western Nevada. (reference #542)
Moderate damage (VII) at Thermalito and in the Oroville area. Ten people treated for minor injuries. Felt area was approximately 120,000 sq km, estimated 3.0 million dollars damage. (reference #1053)
Other significant earthquakes nearby
Within 200 km, the deadliest first.
- October 21, 1868, Hayward,san Francisco, California, United States
- October 2, 1969, Santa Rosa, California, United States
- August 24, 2014, Napa, Vallejo, California, United States
- November 13, 1851, Northern, California, United States
- April 21, 1892, Winters, California, United States
- March 7, 1865, E Central, Sonoma County, California, United States
- April 19, 1892, Vacaville,winters, California, United States
- April 26, 2008, Fallon, Nevada, United States
- September 3, 2000, Napa, California, United States
- March 31, 1898, Sonoma County, California, United States
- June 10, 1836, California, United States
- January 24, 1980, Livermore, California, United States
- July 20, 2007, Montclair, California, United States
- May 15, 1851, Northern, California, United States
- October 22, 1854, Northern, California, United States
More
Significant earthquakes of 1975The 1900sEvery quake the USGS located in 1975Recent 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 2026-09-24. NCEI earthquake 4696.