QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Ukiah, CA

Yes: an earthquake was likely felt in Ukiah in the last 24 hours. M 1.5, 5 km (3 mi) E of Ukiah, at 3:26 am PST on 12 November 2026 (11:26 UTC); the estimated shaking in Ukiah was intensity II (weak). Every earthquake near Ukiah

This page: a magnitude 1.5 earthquake was recorded 27 km (17 mi) west-northwest of Ukiah, CA, at 4:37 pm PDT on 21 March 2021 (23:37 UTC), less than 1 km deep.

USGS: 22km E of Navarro Head, CA

4:37 pm PDT, Mar 21, 2021 · · 0.9 km deep · released about 5.7 lb of TNT

10 km30 km60 km120 km N Mendocino County 25 kmLake County 67 kmSonoma County 91 kmGlenn County 104 kmColusa County 109 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
4:37 pm PDT on 21 March 2021 ()
Where
27 km (17 mi) west-northwest of Ukiah, CA · earthquakes near Ukiah
Magnitude
M 1.5 (md)
Depth
0.9 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 25 km NNE
Nearest mapped fault
Maacama fault, 24 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 2059 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 10 km (6 mi) from the epicentre. In Ukiah, 27 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.

Earthquakes near other towns within 30 km: Willits, Boonville, Redwood Valley, Brooktrails.

How big was it?

This earthquake released about 5.7 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 2,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. This earthquake M 1.5 about 5.7 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 4.4 on 2020-12-06 — about 20,000 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 · 37 km ESE 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 39.2133, -123.5052. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 25 km (15 mi) NNE earthquakes near Mendocino County
Lake County, CA 67 km (41 mi) E earthquakes near Lake County
Sonoma County, CA 91 km (57 mi) SSE earthquakes near Sonoma County
Glenn County, CA 104 km (65 mi) ENE earthquakes near Glenn County
Colusa County, CA 109 km (68 mi) E earthquakes near Colusa County
Napa County, CA 129 km (80 mi) SE earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.9 8km NNW of Redwood Valley, CA
  2. 2.0 12km WNW of Lake Pillsbury, CA
  3. 1.8 6km E of Willits, CA
  4. 1.8 9km NNW of Redwood Valley, CA
  5. 2.2 7km E of Willits, CA
  6. 1.7 10km SW of Ukiah, CA
  7. 1.6 7km E of Willits, CA
  8. 1.6 9km NNW of Redwood Valley, CA
  9. 1.7 8km NNW of Redwood Valley, CA
  10. 1.7 19km SW of Laytonville, CA
  11. 1.9 15km N of Brooktrails, CA
  12. 2.9 4km SSE of Redwood Valley, CA
  13. 2.0 12km WNW of Redwood Valley, CA
  14. 1.8 10km NNW of Redwood Valley, CA
  15. 1.6 11km NNE of Boonville, 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.