QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

7km NE of Fort Bragg, 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 27 kmLake County 97 kmGlenn County 116 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, 27 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2678 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 39.4928, -123.7513. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mendocino County, CA 27 km (17 mi) WNW of here earthquakes near Mendocino County
Lake County, CA 97 km (60 mi) WNW of here earthquakes near Lake County
Glenn County, CA 116 km (72 mi) W of here earthquakes near Glenn County
Sonoma County, CA 129 km (80 mi) NNW of here earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 2.1 13km SSW of Laytonville, CA
  2. 1.6 13km SSW of Laytonville, CA
  3. 1.6 12km WNW of Redwood Valley, CA
  4. 3.1 15km ESE of Navarro Head, CA
  5. 2.3 16km SSW of Willits, CA
  6. 2.3 14km SW of Laytonville, CA
  7. 1.9 4km NW of Redwood Valley, CA
  8. 1.9 10km NNW of Redwood Valley, CA
  9. 1.5 16km NE of Brooktrails, CA
  10. 3.5 20km WNW of Fort Bragg, CA
  11. 1.8 14km NNE of Brooktrails, CA
  12. 1.8 12km NW of Laytonville, CA
  13. 2.5 16km ESE of Navarro Head, CA
  14. 1.8 16km ESE of Navarro Head, CA
  15. 1.7 16km ESE of Navarro Head, 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 4.3 on 2019-04-29 — it released about 2,300 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.