QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

9km NNW of Lake Pillsbury, CA

· 7.4 km deep · released about 40 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mendocino County 40 kmLake County 47 kmGlenn County 51 kmColusa County 73 kmTehama County 95 kmSonoma County 108 kmButte County 120 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
7.4 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 40 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1734 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 40 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 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 39.4910, -122.9813. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mendocino County, CA 40 km (25 mi) E of here earthquakes near Mendocino County
Lake County, CA 47 km (29 mi) NNW of here earthquakes near Lake County
Glenn County, CA 51 km (32 mi) WSW of here earthquakes near Glenn County
Colusa County, CA 73 km (45 mi) WNW of here earthquakes near Colusa County
Tehama County, CA 95 km (59 mi) SW of here earthquakes near Tehama County
Sonoma County, CA 108 km (67 mi) N of here earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 1.9 20km NE of Brooktrails, CA
  2. 1.7 6km E of Willits, CA
  3. 2.2 20km NE of Covelo, CA
  4. 2.1 5km E of Covelo, CA
  5. 1.7 9km W of Covelo, CA
  6. 1.9 19km NNE of Alder Springs, CA
  7. 1.9 6km E of Covelo, CA
  8. 1.7 17km SE of Lake Pillsbury, CA
  9. 1.9 2km W of Redwood Valley, CA
  10. 1.6 7km ESE of Redwood Valley, CA
  11. 1.8 5km NW of Lake Pillsbury, CA
  12. 2.0 23km NW of Alder Springs, CA
  13. 2.3 5km E of Covelo, CA
  14. 1.7 5km E of Covelo, CA
  15. 1.9 5km ENE 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 33,000 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.