QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

31 km of Alder Springs, CA

· 5.9 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 51 kmTehama County 55 kmMendocino County 76 kmTrinity County 84 kmLake County 91 kmColusa County 97 kmButte County 108 kmShasta County 114 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 1.8 (md)
Depth
5.9 km below the surface
Felt
no reports yet
Nearest
Glenn County, 51 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 769 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 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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 39.9233, -122.8273. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glenn County, CA 51 km (32 mi) NW of here earthquakes near Glenn County
Tehama County, CA 55 km (34 mi) WSW of here earthquakes near Tehama County
Mendocino County, CA 76 km (47 mi) NE of here earthquakes near Mendocino County
Trinity County, CA 84 km (52 mi) SSE of here earthquakes near Trinity County
Lake County, CA 91 km (57 mi) N of here earthquakes near Lake County
Colusa County, CA 97 km (60 mi) NNW of here earthquakes near Colusa County

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

Aftershocks so far

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

  1. 1.9 21 km NW of Alder Springs, CA
  2. 1.7 21 km NW of Alder Springs, CA
  3. 2.4 20 km NW of Alder Springs, CA
  4. 1.6 15 km SSE of Covelo, CA
  5. 1.7 20 km NW of Alder Springs, CA
  6. 1.8 20 km NW of Alder Springs, CA
  7. 1.7 21 km NW of Alder Springs, CA
  8. 1.7 10 km N of Lake Pillsbury, CA
  9. 1.9 33 km ENE of Covelo, CA
  10. 2.9 21 km NW of Alder Springs, CA
  11. 2.5 20 km NW of Alder Springs, CA
  12. 2.0 21 km NW of Alder Springs, CA
  13. 2.1 21 km NW of Alder Springs, CA
  14. 1.7 7 km E of Covelo, CA
  15. 2.1 23 km NW of Alder Springs, 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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.