QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Fort Bragg, CA

No earthquake was likely felt in Fort Bragg in the 24 hours to 4:22 am PST (12:22 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 2.4 earthquake was recorded 34 km (21 mi) north-northeast of Fort Bragg, CA, at 5:24 am PST on 7 January 2023 (13:24 UTC), 8.0 km deep. 2 people have reported feeling it to USGS.

USGS: 14km E of Rockport, CA

5:24 am PST, Jan 7, 2023 · · 8.0 km deep · released about 120 lb of TNT

10 km30 km60 km120 km N Mendocino County 37 kmLake County 104 kmGlenn County 108 kmHumboldt County 111 kmTrinity County 112 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 am PST on 7 January 2023 ()
Where
34 km (21 mi) north-northeast of Fort Bragg, CA · earthquakes near Fort Bragg
Magnitude
M 2.4 (md)
Depth
8.0 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Mendocino County, 37 km SSE
Nearest mapped fault
Maacama fault, 8 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 1404 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 19 km (12 mi) from the epicentre. In Fort Bragg, 34 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.

Likely felt in: Laytonville 15 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 92,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.2× the energy of this one
  4. This earthquake M 2.4 about 120 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 2017-12-14 — about 640 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.9 9 km S of Leggett, California · 9 km NW of this epicentre
  2. 5.5 7 km ESE of Shelter Cove, California · 42 km NW 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 39.7295, -123.6485. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 37 km (23 mi) SSE earthquakes near Mendocino County
Lake County, CA 104 km (65 mi) SE earthquakes near Lake County
Glenn County, CA 108 km (67 mi) E earthquakes near Glenn County
Humboldt County, CA 111 km (69 mi) NNW earthquakes near Humboldt County
Trinity County, CA 112 km (69 mi) NNE earthquakes near Trinity County

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

Aftershocks so far

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

  1. 1.6 8km E of Willits, CA
  2. 1.6 10km SSW of Cape Vizcaino, CA
  3. 1.7 7km E of Willits, CA
  4. 2.0 16km WNW of Cape Vizcaino, CA
  5. 1.6 5km SE of Willits, CA
  6. 1.8 17km SSE of Shelter Cove, CA
  7. 1.8 18km SSE of Shelter Cove, CA
  8. 1.5 8km ESE of Willits, CA
  9. 1.7 2km NNW of Redway, CA
  10. 2.0 9km NNE of Brooktrails, CA
  11. 1.9 21km ENE of Brooktrails, CA
  12. 1.9 4km NNW of Redway, CA
  13. 1.7 7km E of Willits, CA
  14. 1.8 5km ESE of Redway, CA
  15. 2.0 19km W of Cape Vizcaino, 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.