QuakeIndex

Earthquake · reviewed by a seismologist

M 4.1mw

Earthquake near Covelo, CA

No earthquake was likely felt in Covelo in the 24 hours to 9:51 pm PST (05:51 UTC). The last one was M 2.2, 9 km (6 mi) N, at 3:31 pm PST on 10 November 2026, estimated intensity II (weak) in town. Every earthquake near Covelo

This page: a magnitude 4.1 earthquake was recorded 19 km (12 mi) northwest of Covelo, CA, at 5:24 pm PDT on 3 November 2021 (00:24 UTC), 7.4 km deep. 21 people have reported feeling it to USGS.

USGS: 19km NW of Covelo, CA

5:24 pm PDT, Nov 3, 2021 · · 7.4 km deep · released about 20 tons of TNT

10 km30 km60 km120 km N Mendocino County 51 kmTrinity County 88 kmGlenn County 93 kmHumboldt County 100 kmTehama County 105 kmLake County 105 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
5:24 pm PDT on 3 November 2021 ()
Where
19 km (12 mi) northwest of Covelo, CA · earthquakes near Covelo
Magnitude
M 4.1 (mw)
Depth
7.4 km below the surface
Felt
21 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Nearest
Mendocino County, 51 km S
Nearest mapped fault
Bartlett Springs fault system, 3 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1763 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 103 km (64 mi) from the epicentre. In Covelo, 19 km away, the estimate is intensity III (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Likely felt in: Covelo 19 km, intensity III · Laytonville 23 km, intensity III · Redway 42 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 20 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 8,500× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 380× the energy of this one
  3. Magna, Utah 2020 M 5.7 270× the energy of this one
  4. This earthquake M 4.1 about 20 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 42× more

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.

For this area

The largest earthquake within 50 km since 2016 was M 4.3 on 2017-12-14 — about 1.9 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.9 9 km S of Leggett, California · 29 km WSW of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 39.8938, -123.4245. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 51 km (32 mi) S earthquakes near Mendocino County
Trinity County, CA 88 km (55 mi) NNE earthquakes near Trinity County
Glenn County, CA 93 km (58 mi) ESE earthquakes near Glenn County
Humboldt County, CA 100 km (62 mi) NNW earthquakes near Humboldt County
Tehama County, CA 105 km (65 mi) ENE earthquakes near Tehama County
Lake County, CA 105 km (65 mi) SE earthquakes near Lake County

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

Aftershocks so far

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

  1. 1.9 23km NE of Redway, CA
  2. 1.7 9km W of Covelo, CA
  3. 1.9 6km E of Covelo, CA
  4. 2.0 23km NW of Alder Springs, CA
  5. 2.3 5km E of Covelo, CA
  6. 1.7 5km E of Covelo, CA
  7. 2.1 7km W of Redway, CA
  8. 1.9 5km ENE of Covelo, CA
  9. 1.8 6km E of Covelo, CA
  10. 2.0 5km ENE of Covelo, CA
  11. 1.9 5km ENE of Covelo, CA
  12. 1.7 6km E of Covelo, CA
  13. 2.9 6km E of Covelo, CA
  14. 1.8 8km SSE of Laytonville, CA
  15. 1.8 7km ENE of Covelo, 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.