QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

12km W of Alder Springs, CA

· 1.7 km deep · released about 630 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 40 kmMendocino County 56 kmLake County 63 kmTehama County 74 kmColusa County 76 kmButte County 108 kmTrinity County 111 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 2.9 (md)
Depth
1.7 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Glenn County, 40 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1810 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 2 people have reported feeling it to USGS.

How big was it?

This earthquake released about 630 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 24,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 17,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.5× the energy of this one
  4. This earthquake M 2.9 about 630 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.

Where

Epicentre 39.6677, -122.8608. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glenn County, CA 40 km (25 mi) W of here earthquakes near Glenn County
Mendocino County, CA 56 km (35 mi) ENE of here earthquakes near Mendocino County
Lake County, CA 63 km (39 mi) N of here earthquakes near Lake County
Tehama County, CA 74 km (46 mi) SW of here earthquakes near Tehama County
Colusa County, CA 76 km (47 mi) NW of here earthquakes near Colusa County
Butte County, CA 108 km (67 mi) W of here earthquakes near Butte County

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

Aftershocks so far

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

  1. 1.6 14km NNE of Brooktrails, CA
  2. 1.7 14km SE of Lake Pillsbury, CA
  3. 2.0 1km WNW of Stony Gorge Reservoir, CA
  4. 1.7 10km NNW of Redwood Valley, CA
  5. 1.8 7km ENE of Brooktrails, CA
  6. 1.5 13km N of Brooktrails, CA
  7. 1.8 13km WNW of Alder Springs, CA
  8. 2.8 11km NE of Covelo, CA
  9. 1.7 14km NNE of Brooktrails, CA
  10. 1.6 9km E of Willits, CA
  11. 1.8 13km W of Alder Springs, CA
  12. 2.1 12km WNW of Alder Springs, CA
  13. 1.8 8km NNW of Redwood Valley, CA
  14. 1.6 10km N of Lake Pillsbury, CA
  15. 2.9 10km N of Lake Pillsbury, 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 5.1 on 2016-08-10 — it released about 2,100 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.