QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Hayfork, CA

No earthquake was likely felt in Hayfork in the 24 hours to 4:40 am PST (12:40 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 2.4 earthquake was recorded 19 km (12 mi) southwest of Hayfork, CA, at 8:35 am PDT on 26 May 2025 (15:35 UTC), 34 km deep.

USGS: 19 km SW of Hayfork, CA

8:35 am PDT, May 26, 2025 · · 34 km deep · released about 120 lb of TNT

10 km30 km60 km120 km N Trinity County 31 kmHumboldt County 60 kmTehama County 98 kmMendocino County 110 kmShasta County 115 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
8:35 am PDT on 26 May 2025 ()
Where
19 km (12 mi) southwest of Hayfork, CA · earthquakes near Hayfork
Magnitude
M 2.4 (md)
Depth
34 km below the surface
Felt
no reports yet
Nearest
Trinity County, 31 km NE
Nearest mapped fault
Bartlett Springs fault system, 23 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 527 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Hayfork, 19 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 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 92,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.2× the energy of this one
  4. This earthquake M 2.4 about 120 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 1,400 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.6 15 km SW of Burnt Ranch, California · 41 km NW of this epicentre
  2. 5.4 3 km NNW of Burnt Ranch, California · 48 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 40.4208, -123.3260. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 31 km (19 mi) NE earthquakes near Trinity County
Humboldt County, CA 60 km (37 mi) WNW earthquakes near Humboldt County
Tehama County, CA 98 km (61 mi) ESE earthquakes near Tehama County
Mendocino County, CA 110 km (69 mi) S earthquakes near Mendocino County
Shasta County, CA 115 km (71 mi) ENE earthquakes near Shasta County
Glenn County, CA 120 km (75 mi) SE earthquakes near Glenn County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

42 earthquakes have been recorded within 50 km since this one.

  1. 2.4 28 km ESE of Rio Dell, CA
  2. 2.5 42 km N of Covelo, CA
  3. 1.9 25 km SSW of Willow Creek, CA
  4. 1.8 32 km S of Willow Creek, CA
  5. 1.9 26 km NE of Redway, CA
  6. 1.9 23 km SSW of Willow Creek, CA
  7. 2.0 17 km NE of Redway, CA
  8. 1.8 18 km S of Hayfork, CA
  9. 2.1 28 km W of Hayfork, CA
  10. 2.0 31 km NNW of Covelo, CA
  11. 1.5 30 km NNW of Covelo, CA
  12. 1.9 18 km NNE of Redway, CA
  13. 2.3 37 km WSW of Hayfork, CA
  14. 2.0 12 km SSW of Hayfork, CA
  15. 2.0 23 km E 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.