QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

Earthquake near Hayfork, CA

No earthquake was likely felt in Hayfork in the 24 hours to 5:24 am PST (13:24 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 2.0 earthquake was recorded 39 km (24 mi) southwest of Hayfork, CA, at 9:07 pm PDT on 4 April 2019 (04:07 UTC), 30 km deep.

USGS: 34km NE of Redway, CA

9:07 pm PDT, Apr 4, 2019 · · 30 km deep · released about 31 lb of TNT

10 km30 km60 km120 km N Trinity County 50 kmHumboldt County 55 kmMendocino County 99 kmTehama County 111 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
9:07 pm PDT on 4 April 2019 ()
Where
39 km (24 mi) southwest of Hayfork, CA · earthquakes near Hayfork
Magnitude
M 2.0 (md)
Depth
30 km below the surface
Felt
no reports yet
Nearest
Trinity County, 50 km NE
Nearest mapped fault
Bartlett Springs fault system, 12 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 2774 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, 39 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 31 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 480,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 340,000× the energy of this one
  3. Around the size people start to feel M 3.0 31× the energy of this one
  4. This earthquake M 2.0 about 31 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 5,200 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.6 15 km SW of Burnt Ranch, California · 45 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 40.3170, -123.5177. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 50 km (31 mi) NE earthquakes near Trinity County
Humboldt County, CA 55 km (34 mi) NW earthquakes near Humboldt County
Mendocino County, CA 99 km (61 mi) S earthquakes near Mendocino County
Tehama County, CA 111 km (69 mi) E earthquakes near Tehama County
Glenn County, CA 124 km (77 mi) SE earthquakes near Glenn County

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

Aftershocks so far

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

  1. 2.1 4km N of Redway, CA
  2. 1.7 5km ENE of Redway, CA
  3. 1.7 4km NW of Redway, CA
  4. 2.1 4km NW of Redway, CA
  5. 2.0 38km W of Hayfork, CA
  6. 3.1 3km NW of Redway, CA
  7. 2.2 20km SE of Rio Dell, CA
  8. 2.9 20km SE of Rio Dell, CA
  9. 1.8 19km SE of Rio Dell, CA
  10. 2.6 41km S of Hayfork, CA
  11. 2.7 37km SSE of Hayfork, CA
  12. 1.6 9km ESE of Hydesville, CA
  13. 2.9 16km N of Redway, CA
  14. 2.0 3km NNW of Redway, CA
  15. 1.5 4km N of Redway, 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.