QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Greenville, CA

No earthquake was likely felt in Greenville in the 24 hours to 3:25 am PST (11:25 UTC). The last one was M 2.3, 18 km (11 mi) SSE, at 5:11 am PST on 7 November 2026, estimated intensity II (weak) in town. Every earthquake near Greenville

This page: a magnitude 2.4 earthquake was recorded 11 km (7 mi) west-northwest of Greenville, CA, at 9:21 pm PDT on 21 May 2023 (04:21 UTC), 5.9 km deep.

USGS: 1km S of Canyondam, CA

9:21 pm PDT, May 21, 2023 · · 5.9 km deep · released about 110 lb of TNT

Every earthquake near Greenville Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Plumas County 29 kmButte County 71 kmLassen County 73 kmSierra County 80 kmTehama County 98 kmNevada County 100 kmYuba County 102 kmShasta County 105 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
9:21 pm PDT on 21 May 2023 ()
Where
11 km (7 mi) west-northwest of Greenville, CA · earthquakes near Greenville
Magnitude
M 2.4 (md)
Depth
5.9 km below the surface
Felt
no reports yet
Nearest
Plumas County, 29 km SE
Nearest mapped fault
Almanor fault, under 1 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 1270 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 20 km (12 mi) from the epicentre. In Greenville, 11 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.

Likely felt in: Greenville 11 km, intensity II · Westwood 17 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 110 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 140,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 99,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.8× the energy of this one
  4. This earthquake M 2.4 about 110 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

The largest earthquake within 50 km since 2016 was M 5.5 on 2023-05-11 — about 46,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.7 2 km NNE of Canyondam, California · 4 km NNE of this epicentre
  2. 5.5 15 km NE of Mineral, California · 46 km NW 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 40.1620, -121.0765. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Plumas County, CA 29 km (18 mi) SE earthquakes near Plumas County
Butte County, CA 71 km (44 mi) SW earthquakes near Butte County
Lassen County, CA 73 km (45 mi) NNE earthquakes near Lassen County
Sierra County, CA 80 km (50 mi) SE earthquakes near Sierra County
Tehama County, CA 98 km (61 mi) W earthquakes near Tehama County
Nevada County, CA 100 km (62 mi) SSE earthquakes near Nevada County

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

Aftershocks so far

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

  1. 1.7 4 km NNE of Canyondam, CA
  2. 1.8 1 km ENE of Almanor, CA
  3. 2.4 4 km WSW of Hamilton Branch, CA
  4. 2.1 10 km SW of Almanor, CA
  5. 2.5 2 km NNE of Canyondam, CA
  6. 1.9 4 km NW of Almanor, CA
  7. 2.9 1 km ESE of Almanor, CA
  8. 2.2 1 km N of Almanor, CA
  9. 2.1 1 km NNE of Almanor, CA
  10. 1.9 1 km N of Prattville, CA
  11. 2.1 1 km NNE of Almanor, CA
  12. 2.7 2 km NNE of Almanor, CA
  13. 2.3 3 km N of Almanor, CA
  14. 2.2 3 km NNE of Almanor, CA
  15. 2.5 2 km NNE of Almanor, 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.