QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

12km N of Alder Springs, CA

· 39 km deep · released about 46 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 31 kmTehama County 57 kmLake County 73 kmMendocino County 73 kmColusa County 76 kmButte County 94 kmTrinity County 105 kmSutter County 118 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 2.1 (md)
Depth
39 km below the surface
Felt
no reports yet
Nearest
Glenn County, 31 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2606 days ago

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

How big was it?

This earthquake released about 46 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 330,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 230,000× the energy of this one
  3. Around the size people start to feel M 3.0 21× the energy of this one
  4. This earthquake M 2.1 about 46 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 39.7597, -122.7008. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glenn County, CA 31 km (19 mi) NW of here earthquakes near Glenn County
Tehama County, CA 57 km (35 mi) SW of here earthquakes near Tehama County
Lake County, CA 73 km (45 mi) N of here earthquakes near Lake County
Mendocino County, CA 73 km (46 mi) ENE of here earthquakes near Mendocino County
Colusa County, CA 76 km (47 mi) NNW of here earthquakes near Colusa County
Butte County, CA 94 km (59 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

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

  1. 1.8 4km ESE of Lake Pillsbury, CA
  2. 1.8 13km SSE of Covelo, CA
  3. 1.6 24km NW of Alder Springs, CA
  4. 2.6 23km NW of Alder Springs, CA
  5. 1.6 30km NNW of Alder Springs, CA
  6. 1.8 27km ENE of Covelo, CA
  7. 2.1 30km NNW of Alder Springs, CA
  8. 1.5 13km SE of Covelo, CA
  9. 1.6 13km WNW of Alder Springs, CA
  10. 1.6 16km N of Lake Pillsbury, CA
  11. 1.9 5km NNE of Alder Springs, CA
  12. 1.8 14km NE of Covelo, CA
  13. 1.5 16km N of Lake Pillsbury, CA
  14. 1.7 12km NNW of Stony Gorge Reservoir, CA
  15. 1.8 41km NE 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 5.1 on 2016-08-10 — it released about 29,000 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.