QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

37km NNW of Alder Springs, CA

· 10 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Tehama County 54 kmGlenn County 55 kmTrinity County 79 kmMendocino County 79 kmLake County 96 kmColusa County 102 kmButte County 110 kmShasta County 110 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
10 km below the surface
Felt
no reports yet
Nearest
Tehama County, 54 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2921 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 16 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 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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 39.9705, -122.8335. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Tehama County, CA 54 km (34 mi) WSW of here earthquakes near Tehama County
Glenn County, CA 55 km (34 mi) NW of here earthquakes near Glenn County
Trinity County, CA 79 km (49 mi) SSE of here earthquakes near Trinity County
Mendocino County, CA 79 km (49 mi) NE of here earthquakes near Mendocino County
Lake County, CA 96 km (60 mi) N of here earthquakes near Lake County
Colusa County, CA 102 km (63 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

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

  1. 1.8 36km NE of Covelo, CA
  2. 2.6 41km S of Hayfork, CA
  3. 2.7 37km SSE of Hayfork, CA
  4. 1.5 41km NE of Covelo, CA
  5. 2.9 15km N of Lake Pillsbury, CA
  6. 1.9 21km W of Rancho Tehama Reserve, CA
  7. 1.7 8km ENE of Covelo, CA
  8. 1.9 19km NNW of Alder Springs, CA
  9. 1.8 20km NNW of Alder Springs, CA
  10. 2.4 14km NW of Alder Springs, CA
  11. 1.8 23km WNW of Alder Springs, CA
  12. 1.8 16km NW of Alder Springs, CA
  13. 1.6 24km W of Rancho Tehama Reserve, CA
  14. 2.3 15km NNE of Alder Springs, CA
  15. 2.0 14km NNE 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.