QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

5km NNE of Alder Springs, CA

· 11 km deep · released about 23 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 28 kmTehama County 63 kmLake County 65 kmMendocino County 70 kmColusa County 70 kmButte County 94 kmTrinity County 112 kmSutter County 113 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 1.9 (md)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Glenn County, 28 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2386 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 23 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 660,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 470,000× the energy of this one
  3. Around the size people start to feel M 3.0 42× the energy of this one
  4. This earthquake M 1.9 about 23 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 39.6947, -122.7028. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glenn County, CA 28 km (17 mi) WNW of here earthquakes near Glenn County
Tehama County, CA 63 km (39 mi) SW of here earthquakes near Tehama County
Lake County, CA 65 km (41 mi) N of here earthquakes near Lake County
Mendocino County, CA 70 km (43 mi) ENE of here earthquakes near Mendocino County
Colusa County, CA 70 km (43 mi) NW 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

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

  1. 1.7 21km SE of Covelo, CA
  2. 2.1 20km NNW of Lake Pillsbury, CA
  3. 2.0 20km NE of Brooktrails, CA
  4. 1.9 20km NNW of Lake Pillsbury, CA
  5. 1.6 18km SE of Lake Pillsbury, CA
  6. 1.9 18km NW of Lake Pillsbury, CA
  7. 2.2 20km NNW of Lake Pillsbury, CA
  8. 1.9 41km NE of Covelo, CA
  9. 1.8 30km NE of Covelo, CA
  10. 2.6 17km NE of Upper Lake, CA
  11. 1.8 4km ESE of Lake Pillsbury, CA
  12. 1.6 18km NNE of Nice, CA
  13. 2.3 18km NNE of Nice, CA
  14. 1.8 13km SSE of Covelo, CA
  15. 1.6 20km NE of Brooktrails, 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 57,000 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.