Earthquake · reviewed by a seismologist
M 2.7ml
Earthquake near Hayfork, CA
No earthquake was likely felt in Hayfork in the 24 hours to 6:22 am PST (14:22 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 2.7 earthquake was recorded 37 km (23 mi) south-southeast of Hayfork, CA, at 8:55 am PST on 11 December 2019 (16:55 UTC), 42 km deep.
USGS: 37km SSE of Hayfork, CA
- When
- 8:55 am PST on 11 December 2019 ()
- Where
- 37 km (23 mi) south-southeast of Hayfork, CA · earthquakes near Hayfork
- Magnitude
- M 2.7 (ml)
- Depth
- 42 km below the surface
- Felt
- no reports yet
- Nearest
- Trinity County, 46 km N
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2527 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth it was probably too small to be felt, even directly above it. In Hayfork, 37 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 360 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 42,000× the energy of this one
- Magna, Utah 2020 M 5.7 30,000× the energy of this one
- Around the size people start to feel M 3.0 2.6× the energy of this one
- This earthquake M 2.7 about 360 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 4.5 on 2016-08-28 — about 450 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.5 33 km NW of Rancho Tehama Reserve, California · 28 km E 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 40.2395, -123.0345. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Trinity County, CA | 46 km (29 mi) | N | earthquakes near Trinity County |
| Tehama County, CA | 69 km (43 mi) | E | earthquakes near Tehama County |
| Glenn County, CA | 89 km (55 mi) | SE | earthquakes near Glenn County |
| Humboldt County, CA | 92 km (57 mi) | NW | earthquakes near Humboldt County |
| Mendocino County, CA | 96 km (60 mi) | SSW | earthquakes near Mendocino County |
| Shasta County, CA | 102 km (63 mi) | NE | earthquakes near Shasta County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
27 earthquakes have been recorded within 50 km since this one.
- 1.6 19km NE of Covelo, CA
- 2.1 34km NE of Redway, CA
- 1.6 10km NW of Covelo, CA
- 2.2 41km SE of Hayfork, CA
- 1.9 41km NE of Covelo, CA
- 1.8 30km NE of Covelo, CA
- 2.9 32km SSW of Hayfork, CA
- 2.3 26km WSW of Hayfork, CA
- 1.6 24km NW of Alder Springs, CA
- 2.6 23km NW of Alder Springs, CA
- 1.9 6km N of Hayfork, CA
- 1.6 30km NNW of Alder Springs, CA
- 1.8 27km ENE of Covelo, CA
- 2.1 30km NNW of Alder Springs, CA
- 2.3 36km SSW of Hayfork, 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.