QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

Earthquake near Redwood Valley, CA

Yes: an earthquake was likely felt in Redwood Valley in the last 24 hours. M 1.5, 7 km (5 mi) SE of Redwood Valley, at 12:31 pm PST on 11 November 2026 (20:31 UTC); the estimated shaking in Redwood Valley was intensity II (weak). Every earthquake near Redwood Valley

This page: a magnitude 2.6 earthquake was recorded 10 km (6 mi) north-northwest of Redwood Valley, CA, at 7:39 pm PDT on 22 May 2021 (02:39 UTC), 5.2 km deep. 7 people have reported feeling it to USGS.

USGS: 10km NNW of Redwood Valley, CA

7:39 pm PDT, May 22, 2021 · · 5.2 km deep · released about 280 lb of TNT

10 km30 km60 km120 km N Mendocino County 20 kmLake County 50 kmGlenn County 78 kmColusa County 89 kmSonoma County 95 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
7:39 pm PDT on 22 May 2021 ()
Where
10 km (6 mi) north-northwest of Redwood Valley, CA · earthquakes near Redwood Valley
Magnitude
M 2.6 (md)
Depth
5.2 km below the surface
Felt
7 reports · strongest reported intensity III
Nearest
Mendocino County, 20 km WNW
Nearest mapped fault
Maacama fault, 7 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 1930 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 24 km (15 mi) from the epicentre. In Redwood Valley, 10 km away, the estimate is intensity III (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.

Likely felt in: Willits 12 km, intensity II · Brooktrails 16 km, intensity II · Ukiah 22 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 280 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 55,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 39,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.5× the energy of this one
  4. This earthquake M 2.6 about 280 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 5.1 on 2016-08-10 — about 4,700 times the energy of this one.

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

  1. 5.2 6 km ESE of Talmage, California · 29 km SSE 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 39.3453, -123.2448. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 20 km (12 mi) WNW earthquakes near Mendocino County
Lake County, CA 50 km (31 mi) ESE earthquakes near Lake County
Glenn County, CA 78 km (48 mi) ENE earthquakes near Glenn County
Colusa County, CA 89 km (55 mi) ESE earthquakes near Colusa County
Sonoma County, CA 95 km (59 mi) SSE earthquakes near Sonoma County
Napa County, CA 122 km (76 mi) SE earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.6 12km N of Brooktrails, CA
  2. 1.5 5km E of Boonville, CA
  3. 2.3 6km E of Willits, CA
  4. 1.6 13km SE of Talmage, CA
  5. 1.9 14km SSW of Lake Pillsbury, CA
  6. 1.6 6km S of Fort Bragg, CA
  7. 1.7 4km NW of Redwood Valley, CA
  8. 1.8 7km W of Laytonville, CA
  9. 2.4 11km W of Laytonville, CA
  10. 1.6 7km ENE of Brooktrails, CA
  11. 1.5 16km SSW of Willits, CA
  12. 1.8 13km W of Lakeport, CA
  13. 1.7 17km NNE of Nice, CA
  14. 1.5 8km ESE of Willits, CA
  15. 2.0 15km WNW of Lake Pillsbury, 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.