QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

12km NW of Alder Springs, CA

· 3.5 km deep · released about 38 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 39 kmMendocino County 62 kmTehama County 67 kmLake County 69 kmColusa County 79 kmButte County 105 kmTrinity County 106 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
3.5 km below the surface
Felt
no reports yet
Nearest
Glenn County, 39 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1332 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 38 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 5.8 390,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 280,000× the energy of this one
  3. Around the size people start to feel M 3.0 25× the energy of this one
  4. This earthquake M 2.1 about 38 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 39.7248, -122.8258. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glenn County, CA 39 km (24 mi) WNW of here earthquakes near Glenn County
Mendocino County, CA 62 km (39 mi) ENE of here earthquakes near Mendocino County
Tehama County, CA 67 km (42 mi) SW of here earthquakes near Tehama County
Lake County, CA 69 km (43 mi) N of here earthquakes near Lake County
Colusa County, CA 79 km (49 mi) NW of here earthquakes near Colusa County
Butte County, CA 105 km (65 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

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

  1. 1.9 13km WNW of Alder Springs, CA
  2. 2.8 41km NNE of Covelo, CA
  3. 1.6 8km NE of Brooktrails, CA
  4. 1.7 15km SE of Lake Pillsbury, CA
  5. 1.8 5km ESE of Lake Pillsbury, CA
  6. 1.8 8km NE of Lake Pillsbury, CA
  7. 2.2 6km SE of Lake Pillsbury, CA
  8. 2.1 40km NE of Covelo, CA
  9. 1.8 12km ESE of Laytonville, CA
  10. 1.8 6km ESE of Lake Pillsbury, CA
  11. 1.7 14km SE of Lake Pillsbury, CA
  12. 1.6 13km SE of Lake Pillsbury, CA
  13. 2.0 4km NE of Lake Pillsbury, CA
  14. 1.7 15km SE of Lake Pillsbury, CA
  15. 2.5 15km SE 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 34,000 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.