QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Fort Bragg, CA

No earthquake was likely felt in Fort Bragg in the 24 hours to 12:12 am PST (08:12 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 1.7 earthquake was recorded 33 km (21 mi) north-northeast of Fort Bragg, CA, at 6:32 pm PDT on 30 August 2022 (01:32 UTC), less than 1 km deep.

USGS: 14km E of Rockport, CA

6:32 pm PDT, Aug 30, 2022 · · -0.7 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Mendocino County 37 kmLake County 104 kmGlenn County 108 kmHumboldt County 112 kmTrinity County 113 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
6:32 pm PDT on 30 August 2022 ()
Where
33 km (21 mi) north-northeast of Fort Bragg, CA · earthquakes near Fort Bragg
Magnitude
M 1.7 (md)
Depth
-0.7 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 37 km SSE
Nearest mapped fault
Maacama fault, 9 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 1534 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 13 km (8 mi) from the epicentre. In Fort Bragg, 33 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.

Earthquakes near other towns within 30 km: Laytonville.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 930,000× the energy of this one
  3. Around the size people start to feel M 3.0 83× the energy of this one
  4. This earthquake M 1.7 about 11 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 6,500 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 · 10 km NW of this epicentre
  2. 5.5 7 km ESE of Shelter Cove, California · 43 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 39.7203, -123.6560. 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 (64 mi) SE earthquakes near Lake County
Glenn County, CA 108 km (67 mi) E earthquakes near Glenn County
Humboldt County, CA 112 km (70 mi) NNW earthquakes near Humboldt County
Trinity County, CA 113 km (70 mi) NNE earthquakes near Trinity County

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

Aftershocks so far

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

  1. 1.6 16km ENE of Brooktrails, CA
  2. 1.5 11km NNE of Brooktrails, CA
  3. 1.8 8km ESE of Redway, CA
  4. 1.7 20km NNE of Rockport, CA
  5. 1.9 11km W of Laytonville, CA
  6. 2.5 5km E of Covelo, CA
  7. 1.7 19km NNW of Laytonville, CA
  8. 1.5 16km NNW of Laytonville, CA
  9. 1.9 8km ENE of Brooktrails, CA
  10. 1.9 5km E of Covelo, CA
  11. 1.8 4km E of Covelo, CA
  12. 1.5 4km SW of Brooktrails, CA
  13. 1.7 12km N of Brooktrails, CA
  14. 1.5 8km NE of Brooktrails, CA
  15. 1.8 8km NE of Brooktrails, 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.