Earthquake · reviewed by a seismologist
M 4.3mw
Earthquake near Hayfork, CA
No earthquake was likely felt in Hayfork in the 24 hours to 10:58 pm PST (06:58 UTC). The last one was M 3.7, 42 km (26 mi) W, at 2:44 pm PDT on 7 September 2026, estimated intensity II (weak) in town; 15 felt reports to USGS. Every earthquake near Hayfork
This page: a magnitude 4.3 earthquake was recorded 36 km (23 mi) southwest of Hayfork, CA, at 12:55 am PDT on 20 October 2022 (07:55 UTC), 33 km deep. 67 people have reported feeling it to USGS.
USGS: 36km NE of Redway, CA
- When
- 12:55 am PDT on 20 October 2022 ()
- Where
- 36 km (23 mi) southwest of Hayfork, CA · earthquakes near Hayfork
- Magnitude
- M 4.3 (mw)
- Depth
- 33 km below the surface
- Felt
- 67 reports · strongest reported intensity V
- Measured shaking
- intensity IV (ShakeMap)
- USGS impact alert
- green
- Nearest
- Trinity County, 48 km NE
- Nearest mapped fault
- Bartlett Springs fault system, 15 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 1337 days ago
Earthquake alerts for Hayfork, CA
Get a notification in this browser when USGS records an earthquake near Hayfork, 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 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 118 km (73 mi) from the epicentre. In Hayfork, 36 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: Redway 36 km, intensity III · Hayfork 36 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 46 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 3,700× the energy of this one
- Mineral, Virginia 2011 M 5.8 170× the energy of this one
- Magna, Utah 2020 M 5.7 120× the energy of this one
- This earthquake M 4.3 about 46 tons of TNT
- Around the size people start to feel M 3.0 this one released 95× 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 4.5 on 2016-08-28 — about 1.8 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.6 15 km SW of Burnt Ranch, California · 41 km NNW 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 40.3495, -123.5185. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Trinity County, CA | 48 km (30 mi) | NE | earthquakes near Trinity County |
| Humboldt County, CA | 53 km (33 mi) | NW | earthquakes near Humboldt County |
| Mendocino County, CA | 102 km (63 mi) | S | earthquakes near Mendocino County |
| Tehama County, CA | 112 km (70 mi) | ESE | earthquakes near Tehama County |
| Glenn County, CA | 126 km (78 mi) | SE | earthquakes near Glenn County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
41 earthquakes have been recorded within 50 km since this one.
- 2.3 14km SE of Rio Dell, CA
- 2.4 12km SE of Rio Dell, CA
- 1.8 11km SE of Rio Dell, CA
- 2.1 11km SE of Rio Dell, CA
- 5.3 15km SE of Rio Dell, CA
- 2.2 17km E of Hydesville, CA
- 2.3 3km NE of Redway, CA
- 2.5 8km E of Hydesville, CA
- 2.2 19km E of Rio Dell, CA
- 1.8 18km E of Hydesville, CA
- 2.1 11km E of Hydesville, CA
- 1.8 11km E of Hydesville, CA
- 2.2 10km ENE of Hydesville, CA
- 4.2 8km E of Hydesville, CA
- 1.8 18km NE of Hydesville, 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.