QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Fort Bragg, CA

No earthquake was likely felt in Fort Bragg in the 24 hours to 8:23 am PST (16:23 UTC). The last one was M 5.0, 186 km (115 mi) NW, at 8:56 pm PST on 4 November 2026, estimated intensity II (weak) in town; 145 felt reports to USGS. Every earthquake near Fort Bragg

This page: a magnitude 1.6 earthquake was recorded 13 km (8 mi) south-southeast of Fort Bragg, CA, at 4:21 am PDT on 6 April 2022 (11:21 UTC), 3.3 km deep.

USGS: 7km NE of Mendocino, CA

4:21 am PDT, Apr 6, 2022 · · 3.3 km deep · released about 7.1 lb of TNT

10 km30 km60 km120 km N Mendocino County 27 kmLake County 89 kmSonoma County 115 kmGlenn County 118 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
4:21 am PDT on 6 April 2022 ()
Where
13 km (8 mi) south-southeast of Fort Bragg, CA · earthquakes near Fort Bragg
Magnitude
M 1.6 (md)
Depth
3.3 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 27 km ENE
Nearest mapped fault
San Andreas fault, 12 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 1681 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 10 km (6 mi) from the epicentre. In Fort Bragg, 13 km away, the estimate is intensity II (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.

How big was it?

This earthquake released about 7.1 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.1 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.

For this area

The largest earthquake within 50 km since 2016 was M 4.3 on 2019-04-29 — about 13,000 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 · 49 km N 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 39.3443, -123.7297. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 27 km (16 mi) ENE earthquakes near Mendocino County
Lake County, CA 89 km (55 mi) ESE earthquakes near Lake County
Sonoma County, CA 115 km (71 mi) SE earthquakes near Sonoma County
Glenn County, CA 118 km (73 mi) ENE earthquakes near Glenn 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. 1.8 9km SSE of Laytonville, CA
  2. 1.6 9km SSE of Willits, CA
  3. 2.2 2km E of Willits, CA
  4. 1.8 2km SW of Redwood Valley, CA
  5. 2.3 9km SSE of Laytonville, CA
  6. 2.0 2km SW of Redwood Valley, CA
  7. 1.9 15km SE of Rockport, CA
  8. 1.7 16km SE of Rockport, CA
  9. 1.7 5km ENE of Willits, CA
  10. 1.7 14km E of Rockport, CA
  11. 2.1 9km ESE of Willits, CA
  12. 1.6 14km WSW of Brooktrails, CA
  13. 1.6 12km NNE of Point Arena, CA
  14. 2.4 3km E of Willits, CA
  15. 1.7 5km ENE of Willits, 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.