Earthquake · reviewed by a seismologist
M 2.2md
Earthquake near Fort Bragg, CA
No earthquake was likely felt in Fort Bragg in the 24 hours to 3:13 am PST (11:13 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 2.2 earthquake was recorded 5 km (3 mi) north of Fort Bragg, CA, at 6:45 am PDT on 20 August 2018 (13:45 UTC), 6.4 km deep.
USGS: 5km N of Fort Bragg, CA
- When
- 6:45 am PDT on 20 August 2018 ()
- Where
- 5 km (3 mi) north of Fort Bragg, CA · earthquakes near Fort Bragg
- Magnitude
- M 2.2 (md)
- Depth
- 6.4 km below the surface
- Felt
- no reports yet
- Nearest
- Mendocino County, 32 km E
- Nearest mapped fault
- Noyo Basin 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 3005 days ago
Earthquake alerts for Fort Bragg, CA
Get a notification in this browser when USGS records an earthquake near Fort Bragg, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 18 km (11 mi) from the epicentre. In Fort Bragg, 5 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: Fort Bragg 5 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 67 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 230,000× the energy of this one
- Magna, Utah 2020 M 5.7 160,000× the energy of this one
- Around the size people start to feel M 3.0 14× the energy of this one
- This earthquake M 2.2 about 67 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 1,100 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.9 9 km S of Leggett, California · 33 km NNE 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 39.4888, -123.8117. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mendocino County, CA | 32 km (20 mi) | E | earthquakes near Mendocino County |
| Lake County, CA | 101 km (63 mi) | ESE | earthquakes near Lake County |
| Sonoma County, CA | 132 km (82 mi) | SE | earthquakes near Sonoma County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 1.6 2km SW of Laytonville, CA
- 2.1 3km ESE of Rockport, CA
- 1.7 16km ESE of Navarro Head, CA
- 1.8 16km ESE of Navarro Head, CA
- 3.2 18km ESE of Navarro Head, CA
- 1.8 15km SE of Rockport, CA
- 1.5 6km ESE of Willits, CA
- 1.7 13km SE of Laytonville, CA
- 1.6 4km SE of Willits, CA
- 2.0 7km ENE of Brooktrails, CA
- 1.8 14km NNE of Brooktrails, CA
- 1.8 3km N of Brooktrails, CA
- 1.6 10km SE of Willits, CA
- 2.0 8km SE of Willits, CA
- 1.6 12km N 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.