QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

Earthquake near Covelo, CA

No earthquake was likely felt in Covelo in the 24 hours to 5:37 am PST (13:37 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 1.8 earthquake was recorded 31 km (19 mi) northeast of Covelo, CA, at 11:07 am PDT on 27 July 2020 (18:07 UTC), 3.4 km deep.

USGS: 30km NE of Covelo, CA

11:07 am PDT, Jul 27, 2020 · · 3.4 km deep · released about 17 lb of TNT

10 km30 km60 km120 km N Glenn County 63 kmTehama County 65 kmMendocino County 72 kmTrinity County 77 kmLake County 98 kmColusa County 108 kmHumboldt County 115 kmShasta County 118 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
11:07 am PDT on 27 July 2020 ()
Where
31 km (19 mi) northeast of Covelo, CA · earthquakes near Covelo
Magnitude
M 1.8 (md)
Depth
3.4 km below the surface
Felt
no reports yet
Nearest
Glenn County, 63 km SE
Nearest mapped fault
Bartlett Springs fault system, 22 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 2296 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 13 km (8 mi) from the epicentre. In Covelo, 31 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 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 · 34 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 39.9675, -122.9725. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Glenn County, CA 63 km (39 mi) SE earthquakes near Glenn County
Tehama County, CA 65 km (41 mi) ENE earthquakes near Tehama County
Mendocino County, CA 72 km (45 mi) SW earthquakes near Mendocino County
Trinity County, CA 77 km (48 mi) N earthquakes near Trinity County
Lake County, CA 98 km (61 mi) SSE earthquakes near Lake County
Colusa County, CA 108 km (67 mi) SE earthquakes near Colusa County

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

Aftershocks so far

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

  1. 2.3 12km NNW of Covelo, CA
  2. 1.7 13km N of Lake Pillsbury, CA
  3. 1.6 14km SSE of Covelo, CA
  4. 1.6 8km WSW of Covelo, CA
  5. 1.7 12km WNW of Covelo, CA
  6. 1.8 24km NW of Covelo, CA
  7. 1.7 8km WSW of Covelo, CA
  8. 2.1 6km E of Covelo, CA
  9. 2.3 41km NE of Covelo, CA
  10. 1.9 37km NE of Covelo, CA
  11. 1.7 13km N of Laytonville, CA
  12. 1.8 9km SE of Covelo, CA
  13. 2.3 13km WNW of Covelo, CA
  14. 1.6 19km NE of Covelo, CA
  15. 2.2 12km WNW 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.