QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Hayfork, CA

No earthquake was likely felt in Hayfork in the 24 hours to 8:31 pm PST (04:31 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 1.5 earthquake was recorded 49 km (30 mi) south of Hayfork, CA, at 10:50 am PDT on 3 May 2019 (17:50 UTC), 16 km deep.

USGS: 36km N of Covelo, CA

10:50 am PDT, May 3, 2019 · · 16 km deep · released about 5.4 lb of TNT

10 km30 km60 km120 km N Trinity County 59 kmMendocino County 79 kmTehama County 80 kmGlenn County 87 kmHumboldt County 91 kmLake County 118 kmShasta County 120 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
10:50 am PDT on 3 May 2019 ()
Where
49 km (30 mi) south of Hayfork, CA · earthquakes near Hayfork
Magnitude
M 1.5 (md)
Depth
16 km below the surface
Felt
no reports yet
Nearest
Trinity County, 59 km N
Nearest mapped fault
Bartlett Springs fault system, 20 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 2749 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, 49 km away, the estimate is intensity I (not felt). 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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 31,000 times the energy of this one.

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

  1. 5.5 33 km NW of Rancho Tehama Reserve, California · 41 km ENE 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 40.1162, -123.1767. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 59 km (37 mi) N earthquakes near Trinity County
Mendocino County, CA 79 km (49 mi) SSW earthquakes near Mendocino County
Tehama County, CA 80 km (50 mi) E earthquakes near Tehama County
Glenn County, CA 87 km (54 mi) SE earthquakes near Glenn County
Humboldt County, CA 91 km (57 mi) NW earthquakes near Humboldt County
Lake County, CA 118 km (73 mi) SSE earthquakes near Lake County

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

Aftershocks so far

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

  1. 2.4 9km W of Covelo, CA
  2. 1.9 21km NNE of Redway, CA
  3. 2.9 32km SSW of Hayfork, CA
  4. 2.3 26km WSW of Hayfork, CA
  5. 1.8 13km SSE of Covelo, CA
  6. 1.6 24km NW of Alder Springs, CA
  7. 2.6 23km NW of Alder Springs, CA
  8. 1.6 30km NNW of Alder Springs, CA
  9. 1.8 27km ENE of Covelo, CA
  10. 2.1 30km NNW of Alder Springs, CA
  11. 2.3 36km SSW of Hayfork, CA
  12. 1.6 31km WSW of Hayfork, CA
  13. 1.5 13km SE of Covelo, CA
  14. 1.9 12km NNW of Covelo, CA
  15. 1.6 11km NNW 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.