QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

Earthquake near Hamilton City, CA

No earthquake was likely felt in Hamilton City in the 24 hours to 9:50 am PST (17:50 UTC). The last one was M 4.0, 85 km (53 mi) WSW, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Hamilton City

This page: a magnitude 2.3 earthquake was recorded 14 km (9 mi) south of Hamilton City, CA, at 1:40 am PDT on 4 May 2023 (08:40 UTC), 22 km deep.

USGS: 14km S of Hamilton City, CA

24 km (15 mi) SW of Chico, CA · 126 km (78 mi) NNW of Sacramento, CA

1:40 am PDT, May 4, 2023 · · 22 km deep · released about 77 lb of TNT

Every earthquake near Hamilton City Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 32 kmButte County 37 kmColusa County 52 kmTehama County 59 kmSutter County 70 kmYuba County 71 kmLake County 83 kmYolo County 105 kmPlumas County 112 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
1:40 am PDT on 4 May 2023 ()
Where
14 km (9 mi) south of Hamilton City, CA · earthquakes near Hamilton City
Magnitude
M 2.3 (md)
Depth
22 km below the surface
Felt
no reports yet
Nearest
Glenn County, 32 km W
Nearest mapped fault
Great Valley thrust fault system, 23 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1288 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Hamilton City, 14 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Willows, Orland, Durham, Chico.

How big was it?

This earthquake released about 77 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 140,000× the energy of this one
  3. Around the size people start to feel M 3.0 12× the energy of this one
  4. This earthquake M 2.3 about 77 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.7 The 1975 Oroville, California Earthquake · 47 km ESE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 39.6147, -122.0338. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Glenn County, CA 32 km (20 mi) W earthquakes near Glenn County
Butte County, CA 37 km (23 mi) E earthquakes near Butte County
Colusa County, CA 52 km (32 mi) SSW earthquakes near Colusa County
Tehama County, CA 59 km (37 mi) NNW earthquakes near Tehama County
Sutter County, CA 70 km (44 mi) SSE earthquakes near Sutter County
Yuba County, CA 71 km (44 mi) ESE earthquakes near Yuba County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

53 earthquakes have been recorded within 50 km since this one.

  1. 2.4 16 km ENE of Willows, CA
  2. 2.0 14 km S of Hamilton City, CA
  3. 2.7 5 km W of Hamilton City, CA
  4. 2.5 9 km E of Rancho Tehama Reserve, CA
  5. 2.5 15 km S of Hamilton City, CA
  6. 2.2 4 km WSW of Hamilton City, CA
  7. 2.0 17 km E of Willows, CA
  8. 2.2 21 km NE of Alder Springs, CA
  9. 1.9 19 km E of Willows, CA
  10. 2.4 9 km S of Hamilton City, CA
  11. 1.9 5 km WSW of Concow, CA
  12. 3.1 9 km ENE of Colusa, CA
  13. 3.2 15 km E of Willows, CA
  14. 2.1 16 km ESE of Willows, CA
  15. 2.3 13 km NNW of Chico, CA

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.