QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

Earthquake near Hayfork, CA

No earthquake was likely felt in Hayfork in the 24 hours to 5:09 am PST (13:09 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 27 km (17 mi) west-northwest of Hayfork, CA, at 12:30 am PDT on 20 October 2019 (07:30 UTC), 29 km deep.

USGS: 27km WNW of Hayfork, CA

12:30 am PDT, Oct 20, 2019 · · 29 km deep · released about 990 lb of TNT

10 km30 km60 km120 km N Trinity County 32 kmHumboldt County 38 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
12:30 am PDT on 20 October 2019 ()
Where
27 km (17 mi) west-northwest of Hayfork, CA · earthquakes near Hayfork
Magnitude
M 3.0 (ml)
Depth
29 km below the surface
Felt
no reports yet
Nearest
Trinity County, 32 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2505 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 23 km (14 mi) from the epicentre. In Hayfork, 27 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 990 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.

  1. Northridge, California 1994 M 6.7 340,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 15,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
  4. This earthquake M 3.0 about 990 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 500 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.4 The 1954 Eureka-Arcata, California Earthquake · 42 km NW of this epicentre
  2. 5.8 Near Eureka, California · 47 km WNW of this epicentre
  3. 5.6 15 km SW of Burnt Ranch, California · 14 km NW of this epicentre
  4. 5.4 3 km NNW of Burnt Ranch, California · 23 km N 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 40.6312, -123.4878. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 32 km (20 mi) E earthquakes near Trinity County
Humboldt County, CA 38 km (24 mi) WNW earthquakes near Humboldt County
Tehama County, CA 120 km (75 mi) ESE earthquakes near Tehama County
Siskiyou County, CA 133 km (83 mi) NE earthquakes near Siskiyou County
Glenn County, CA 147 km (91 mi) SE earthquakes near Glenn 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. 2.4 20km NE of Willow Creek, CA
  2. 2.1 9km NW of Willow Creek, CA
  3. 2.3 15km WSW of Willow Creek, CA
  4. 2.1 28km ENE of Redway, CA
  5. 2.1 26km ESE of Willow Creek, CA
  6. 2.1 23km NNE of Redway, CA
  7. 3.7 30km NNE of Redway, CA
  8. 2.4 8km WNW of Hayfork, CA
  9. 2.1 34km NE of Redway, CA
  10. 2.3 29km W of Hayfork, CA
  11. 2.1 28km NW of Hayfork, CA
  12. 2.1 23km SSW of Willow Creek, CA
  13. 1.8 24km ENE of Hydesville, CA
  14. 1.7 14km ESE of Pine Hills, CA
  15. 1.8 13km E of Willow Creek, 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.