QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Covelo, CA

No earthquake was likely felt in Covelo in the 24 hours to 5:57 pm PST (01:57 UTC). The last one was M 2.2, 9 km (6 mi) N, at 3:31 pm PST on 10 November 2026, estimated intensity II (weak) in town. Every earthquake near Covelo

This page: a magnitude 1.6 earthquake was recorded 25 km (16 mi) northeast of Covelo, CA, at 12:41 pm PDT on 3 April 2018 (19:41 UTC), less than 1 km deep.

USGS: 25km NE of Covelo, CA

12:41 pm PDT, Apr 3, 2018 · · -0.8 km deep · released about 9 lb of TNT

10 km30 km60 km120 km N Mendocino County 68 kmGlenn County 69 kmTehama County 73 kmTrinity County 76 kmLake County 99 kmHumboldt County 111 kmColusa County 112 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
12:41 pm PDT on 3 April 2018 ()
Where
25 km (16 mi) northeast of Covelo, CA · earthquakes near Covelo
Magnitude
M 1.6 (md)
Depth
-0.8 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 68 km SSW
Nearest mapped fault
Bartlett Springs fault system, 18 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 3136 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 12 km (7 mi) from the epicentre. In Covelo, 25 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 9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. This earthquake M 1.6 about 9 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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 · 39 km NE 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 39.9635, -123.0585. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 68 km (42 mi) SSW earthquakes near Mendocino County
Glenn County, CA 69 km (43 mi) SE earthquakes near Glenn County
Tehama County, CA 73 km (45 mi) ENE earthquakes near Tehama County
Trinity County, CA 76 km (47 mi) N earthquakes near Trinity County
Lake County, CA 99 km (61 mi) SSE earthquakes near Lake County
Humboldt County, CA 111 km (69 mi) NW earthquakes near Humboldt County

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

Aftershocks so far

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

  1. 1.8 12km SE of Laytonville, CA
  2. 1.6 25km W of Rancho Tehama Reserve, CA
  3. 1.8 21km N of Laytonville, CA
  4. 1.9 22km N of Laytonville, CA
  5. 1.8 37km NNW of Alder Springs, CA
  6. 1.7 12km SE of Laytonville, CA
  7. 1.9 15km NNW of Laytonville, CA
  8. 1.7 5km WNW of Covelo, CA
  9. 1.7 15km N of Alder Springs, CA
  10. 2.0 44km NNE of Covelo, CA
  11. 1.6 14km SE of Laytonville, CA
  12. 2.0 38km S of Hayfork, CA
  13. 2.1 38km S of Hayfork, CA
  14. 2.1 42km NNE of Covelo, CA
  15. 1.9 25km SE of Hayfork, 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.