QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

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 1.7 earthquake was recorded 10 km (6 mi) southwest of Ukiah, CA, at 6:21 pm PDT on 29 May 2021 (01:21 UTC), less than 1 km deep.

USGS: 10km SW of Ukiah, CA

89 km (55 mi) NW of Santa Rosa, CA

6:21 pm PDT, May 29, 2021 · · 0.9 km deep · released about 12 lb of TNT

10 km30 km60 km120 km N Mendocino County 40 kmLake County 48 kmSonoma County 71 kmColusa County 92 kmGlenn County 96 kmNapa County 107 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
6:21 pm PDT on 29 May 2021 ()
Where
10 km (6 mi) southwest of Ukiah, CA · earthquakes near Ukiah
Magnitude
M 1.7 (md)
Depth
0.9 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 40 km NNW
Nearest mapped fault
Maacama fault, 12 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 1990 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 Ukiah, 10 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: Ukiah 10 km, intensity II · Boonville 11 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 900,000× the energy of this one
  3. Around the size people start to feel M 3.0 80× the energy of this one
  4. This earthquake M 1.7 about 12 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 5.0 on 2016-12-14 — about 83,000 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 · 18 km E 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 39.0942, -123.3015. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 40 km (25 mi) NNW earthquakes near Mendocino County
Lake County, CA 48 km (30 mi) E earthquakes near Lake County
Sonoma County, CA 71 km (44 mi) SSE earthquakes near Sonoma County
Colusa County, CA 92 km (57 mi) E earthquakes near Colusa County
Glenn County, CA 96 km (60 mi) NE earthquakes near Glenn County
Napa County, CA 107 km (66 mi) SE earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.7 11km ESE of Redwood Valley, CA
  2. 1.6 7km ESE of Willits, CA
  3. 2.8 7km ESE of Willits, CA
  4. 2.5 7km ESE of Willits, CA
  5. 1.8 4km NNE of Lake Pillsbury, CA
  6. 1.7 9km SSE of Point Arena, CA
  7. 2.2 12km E of Navarro Head, CA
  8. 1.8 10km SE of Willits, CA
  9. 1.6 8km ENE of Willits, CA
  10. 3.0 9km WNW of The Geysers, CA
  11. 1.8 16km NE of Upper Lake, CA
  12. 1.9 14km SE of Lake Pillsbury, CA
  13. 1.5 10km SE of Willits, CA
  14. 1.9 10km SE of Willits, CA
  15. 1.9 5km SSE of Redwood Valley, 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.