Earthquake · reviewed by a seismologist
M 3.0ml
Earthquake near Hayfork, CA
No earthquake was likely felt in Hayfork in the 24 hours to 6:17 pm PST (02:17 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 3.0 earthquake was recorded 50 km (31 mi) south of Hayfork, CA, at 9:49 am PDT on 12 August 2017 (16:49 UTC), 44 km deep. 9 people have reported feeling it to USGS.
USGS: 26 km SE of Ruth, California
- When
- 9:49 am PDT on 12 August 2017 ()
- Where
- 50 km (31 mi) south of Hayfork, CA · earthquakes near Hayfork
- Magnitude
- M 3.0 (ml)
- Depth
- 44 km below the surface
- Felt
- 9 reports · strongest reported intensity III
- Nearest
- Trinity County, 60 km N
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1605 days ago
Earthquake alerts for Hayfork, CA
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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, 50 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 1,000 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 330,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 15,000× the energy of this one
- Magna, Utah 2020 M 5.7 10,000× the energy of this one
- This earthquake M 3.0 about 1,000 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 160 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 · 33 km ENE 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 40.1132, -123.0790. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Trinity County, CA | 60 km (37 mi) | N | earthquakes near Trinity County |
| Tehama County, CA | 72 km (45 mi) | E | earthquakes near Tehama County |
| Glenn County, CA | 81 km (50 mi) | SE | earthquakes near Glenn County |
| Mendocino County, CA | 82 km (51 mi) | SSW | earthquakes near Mendocino County |
| Humboldt County, CA | 97 km (61 mi) | NW | earthquakes near Humboldt County |
| Shasta County, CA | 113 km (70 mi) | NE | earthquakes near Shasta County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 1.6 16km NNW of Covelo, CA
- 1.5 34km WNW of Rancho Tehama Reserve, CA
- 1.9 37km W of Rancho Tehama Reserve, CA
- 1.7 38km NNW of Alder Springs, CA
- 1.9 28km NW of Alder Springs, CA
- 2.4 41km NE of Covelo, CA
- 1.9 32km NNW of Alder Springs, CA
- 1.6 32km NNW of Alder Springs, CA
- 1.8 39km NE of Covelo, CA
- 1.6 39km NE of Covelo, CA
- 1.7 39km NE of Covelo, CA
- 2.8 40km NE of Covelo, CA
- 2.5 4km E of Covelo, CA
- 1.7 36km NNW of Alder Springs, CA
- 1.7 28km NW of Alder Springs, 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.