QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

20 km NNW of Alder Springs, CA

· 6.7 km deep · released about 1,800 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 45 kmTehama County 64 kmMendocino County 65 kmLake County 78 kmColusa County 88 kmTrinity County 96 kmButte County 108 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
Magnitude
M 3.2 (ml)
Depth
6.7 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Glenn County, 45 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 149 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 1,800 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 190,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 8,500× the energy of this one
  3. Magna, Utah 2020 M 5.7 6,000× the energy of this one
  4. This earthquake M 3.2 about 1,800 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.9× more

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.

Where

Epicentre 39.8038, -122.8572. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glenn County, CA 45 km (28 mi) WNW of here earthquakes near Glenn County
Tehama County, CA 64 km (40 mi) WSW of here earthquakes near Tehama County
Mendocino County, CA 65 km (40 mi) NE of here earthquakes near Mendocino County
Lake County, CA 78 km (48 mi) N of here earthquakes near Lake County
Colusa County, CA 88 km (54 mi) NW of here earthquakes near Colusa County
Trinity County, CA 96 km (60 mi) SSE of here earthquakes near Trinity County

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

Aftershocks so far

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

  1. 1.7 4 km ENE of Covelo, CA
  2. 1.8 4 km ENE of Covelo, CA
  3. 1.6 4 km ENE of Covelo, CA
  4. 2.3 4 km ENE of Covelo, CA
  5. 1.8 4 km ENE of Covelo, CA
  6. 3.2 4 km ENE of Covelo, CA
  7. 1.8 4 km ENE of Covelo, CA
  8. 1.6 4 km E of Covelo, CA
  9. 2.4 4 km E of Covelo, CA
  10. 2.7 4 km E of Covelo, CA
  11. 1.6 4 km E of Covelo, CA
  12. 1.7 4 km E of Covelo, CA
  13. 1.6 4 km E of Covelo, CA
  14. 2.2 4 km E of Covelo, CA
  15. 3.3 4 km E of Covelo, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.2 on 2025-03-17 — it released about 32 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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