Earthquake · reviewed by a seismologist
M 2.5md
Earthquake near Hayfork, CA
No earthquake was likely felt in Hayfork in the 24 hours to 9:35 am PST (17:35 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 2.5 earthquake was recorded 29 km (18 mi) west of Hayfork, CA, at 11:29 am PDT on 25 October 2018 (18:29 UTC), 7.8 km deep.
USGS: 29km W of Hayfork, CA
- When
- 11:29 am PDT on 25 October 2018 ()
- Where
- 29 km (18 mi) west of Hayfork, CA · earthquakes near Hayfork
- Magnitude
- M 2.5 (md)
- Depth
- 7.8 km below the surface
- Felt
- no reports yet
- Nearest
- Trinity County, 37 km ENE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2940 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 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 21 km (13 mi) from the epicentre. In Hayfork, 29 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 160 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 95,000× the energy of this one
- Magna, Utah 2020 M 5.7 68,000× the energy of this one
- Around the size people start to feel M 3.0 6× the energy of this one
- This earthquake M 2.5 about 160 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 4.8 on 2016-07-21 — about 3,100 times the energy of this one.
Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:
- 6.4 The 1954 Eureka-Arcata, California Earthquake · 47 km NW of this epicentre
- 5.6 15 km SW of Burnt Ranch, California · 22 km NNW of this epicentre
- 5.4 3 km NNW of Burnt Ranch, California · 34 km N of this epicentre
- 5.0 2 km E of Rio Dell, California · 47 km W 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 40.5325, -123.5207. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Trinity County, CA | 37 km (23 mi) | ENE | earthquakes near Trinity County |
| Humboldt County, CA | 39 km (24 mi) | WNW | earthquakes near Humboldt County |
| Tehama County, CA | 118 km (73 mi) | ESE | earthquakes near Tehama County |
| Glenn County, CA | 141 km (87 mi) | SE | earthquakes near Glenn County |
| Siskiyou County, CA | 144 km (89 mi) | NE | earthquakes near Siskiyou County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
49 earthquakes have been recorded within 50 km since this one.
- 1.8 17km ESE of Pine Hills, CA
- 1.9 8km S of Blue Lake, CA
- 1.5 28km NNE of Redway, CA
- 1.7 25km NNW of Redway, CA
- 2.2 8km NNE of Hydesville, CA
- 1.8 31km ESE of Rio Dell, CA
- 1.7 8km E of Hydesville, CA
- 2.3 24km E of Hydesville, CA
- 3.8 16km ESE of Pine Hills, CA
- 2.5 7km ESE of Hydesville, CA
- 2.6 6km ESE of Hydesville, CA
- 2.1 9km ENE of Hydesville, CA
- 2.9 22km NNW of Hayfork, CA
- 1.8 15km E of Hydesville, CA
- 2.0 31km W 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.