QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

15km NW of Alder Springs, CA

· 1.4 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glenn County 42 kmMendocino County 61 kmTehama County 68 kmLake County 71 kmColusa County 82 kmTrinity County 103 kmButte County 107 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
1.4 km below the surface
Felt
no reports yet
Nearest
Glenn County, 42 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2728 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 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× 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 39.7390, -122.8543. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glenn County, CA 42 km (26 mi) WNW of here earthquakes near Glenn County
Mendocino County, CA 61 km (38 mi) NE of here earthquakes near Mendocino County
Tehama County, CA 68 km (42 mi) SW of here earthquakes near Tehama County
Lake County, CA 71 km (44 mi) N of here earthquakes near Lake County
Colusa County, CA 82 km (51 mi) NW of here earthquakes near Colusa County
Trinity County, CA 103 km (64 mi) SSE of here earthquakes near Trinity County

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

Aftershocks so far

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

  1. 1.8 13km WNW of Lake Pillsbury, CA
  2. 1.8 17km SE of Lake Pillsbury, CA
  3. 1.9 16km SE of Lake Pillsbury, CA
  4. 1.8 13km SE of Lake Pillsbury, CA
  5. 1.8 16km SE of Lake Pillsbury, CA
  6. 1.6 21km SE of Covelo, CA
  7. 2.7 21km SE of Covelo, CA
  8. 2.4 21km SE of Covelo, CA
  9. 1.6 9km SSE of Lake Pillsbury, CA
  10. 1.7 6km ESE of Lake Pillsbury, CA
  11. 2.0 11km NE of Alder Springs, CA
  12. 1.6 22km NW of Alder Springs, CA
  13. 2.0 19km W of Rancho Tehama Reserve, CA
  14. 1.9 8km SSE of Lake Pillsbury, CA
  15. 1.8 4km SSE 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 95,000 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.