QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

Earthquake near Hayfork, CA

No earthquake was likely felt in Hayfork in the 24 hours to 12:12 am PST (08:12 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 2.3 earthquake was recorded 36 km (22 mi) south-southwest of Hayfork, CA, at 7:25 am PDT on 2 May 2020 (14:25 UTC), 4.6 km deep.

USGS: 36km SSW of Hayfork, CA

7:25 am PDT, May 2, 2020 · · 4.6 km deep · released about 94 lb of TNT

10 km30 km60 km120 km N Trinity County 47 kmHumboldt County 64 kmMendocino County 95 kmTehama County 102 kmGlenn 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
7:25 am PDT on 2 May 2020 ()
Where
36 km (22 mi) south-southwest of Hayfork, CA · earthquakes near Hayfork
Magnitude
M 2.3 (md)
Depth
4.6 km below the surface
Felt
no reports yet
Nearest
Trinity County, 47 km NNE
Nearest mapped fault
Bartlett Springs fault system, 6 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 2380 days ago

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 20 km (12 mi) from the epicentre. In Hayfork, 36 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 94 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 160,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 110,000× the energy of this one
  3. Around the size people start to feel M 3.0 10× the energy of this one
  4. This earthquake M 2.3 about 94 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 1,700 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 40.2862, -123.4132. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 47 km (30 mi) NNE earthquakes near Trinity County
Humboldt County, CA 64 km (40 mi) NW earthquakes near Humboldt County
Mendocino County, CA 95 km (59 mi) S earthquakes near Mendocino County
Tehama County, CA 102 km (63 mi) E earthquakes near Tehama County
Glenn County, CA 115 km (71 mi) SE earthquakes near Glenn County
Shasta County, CA 127 km (79 mi) ENE earthquakes near Shasta County

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

Aftershocks so far

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

  1. 2.2 21km NNE of Rockport, CA
  2. 2.8 21km NNE of Rockport, CA
  3. 2.8 21km NNE of Rockport, CA
  4. 1.6 19km NE of Covelo, CA
  5. 2.2 12km WNW of Covelo, CA
  6. 2.7 12km WNW of Covelo, CA
  7. 2.1 34km NE of Redway, CA
  8. 1.7 12km WNW of Covelo, CA
  9. 2.3 29km W of Hayfork, CA
  10. 1.7 12km NW of Covelo, CA
  11. 1.7 12km WNW of Covelo, CA
  12. 1.5 13km NW of Covelo, CA
  13. 1.6 13km NW of Covelo, CA
  14. 1.8 12km WNW of Covelo, CA
  15. 1.5 12km NW of Covelo, 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.