QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Willits, CA

No earthquake was likely felt in Willits in the 24 hours to 11:40 am PST (19:40 UTC). The last one was M 1.5, 9 km (5 mi) ESE, at 10:30 pm PST on 2 November 2026, estimated intensity II (weak) in town. Every earthquake near Willits

This page: a magnitude 2.4 earthquake was recorded 11 km (7 mi) southeast of Willits, CA, at 9:42 am PDT on 25 March 2021 (16:42 UTC), 6.3 km deep. 2 people have reported feeling it to USGS.

USGS: 10km SE of Willits, CA

9:42 am PDT, Mar 25, 2021 · · 6.3 km deep · released about 140 lb of TNT

10 km30 km60 km120 km N Mendocino County 18 kmLake County 52 kmGlenn County 78 kmColusa County 90 kmSonoma County 97 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
9:42 am PDT on 25 March 2021 ()
Where
11 km (7 mi) southeast of Willits, CA · earthquakes near Willits
Magnitude
M 2.4 (md)
Depth
6.3 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Mendocino County, 18 km WNW
Nearest mapped fault
Maacama fault, 6 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 1989 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 21 km (13 mi) from the epicentre. In Willits, 11 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.

Likely felt in: Willits 11 km, intensity II · Brooktrails 15 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 140 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 110,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 78,000× the energy of this one
  3. Around the size people start to feel M 3.0 6.9× the energy of this one
  4. This earthquake M 2.4 about 140 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 9,400 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 · 30 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 39.3560, -123.2548. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 18 km (11 mi) WNW earthquakes near Mendocino County
Lake County, CA 52 km (32 mi) ESE earthquakes near Lake County
Glenn County, CA 78 km (49 mi) ENE earthquakes near Glenn County
Colusa County, CA 90 km (56 mi) ESE earthquakes near Colusa County
Sonoma County, CA 97 km (60 mi) SSE earthquakes near Sonoma County
Tehama County, CA 122 km (76 mi) NE earthquakes near Tehama County

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

Aftershocks so far

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

  1. 1.6 7km E of Willits, CA
  2. 1.6 9km NNW of Redwood Valley, CA
  3. 1.7 8km NNW of Redwood Valley, CA
  4. 1.7 19km SW of Laytonville, CA
  5. 1.9 15km N of Brooktrails, CA
  6. 2.9 4km SSE of Redwood Valley, CA
  7. 2.0 12km WNW of Redwood Valley, CA
  8. 1.8 10km NNW of Redwood Valley, CA
  9. 1.5 2km WNW of Laytonville, CA
  10. 1.6 11km NNE of Boonville, CA
  11. 1.5 18km NNW of Cloverdale, CA
  12. 2.6 10km NNW of Redwood Valley, CA
  13. 1.7 8km SE of Talmage, CA
  14. 1.7 17km SSE of Talmage, CA
  15. 1.9 8km NW of Laytonville, 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.