QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Ukiah, CA

Yes: an earthquake was likely felt in Ukiah in the last 24 hours. M 1.5, 10 km (6 mi) NE of Ukiah, at 12:31 pm PST on 11 November 2026 (20:31 UTC); the estimated shaking in Ukiah was intensity II (weak). Every earthquake near Ukiah

This page: a magnitude 2.1 earthquake was recorded 33 km (21 mi) north-northeast of Ukiah, CA, at 5:40 am PDT on 7 September 2019 (12:40 UTC), 4.2 km deep.

USGS: 13km WNW of Lake Pillsbury, CA

5:40 am PDT, Sep 7, 2019 · · 4.2 km deep · released about 43 lb of TNT

10 km30 km60 km120 km N Mendocino County 29 kmLake County 48 kmGlenn County 63 kmColusa County 80 kmSonoma County 103 kmTehama 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
5:40 am PDT on 7 September 2019 ()
Where
33 km (21 mi) north-northeast of Ukiah, CA · earthquakes near Ukiah
Magnitude
M 2.1 (md)
Depth
4.2 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 29 km W
Nearest mapped fault
Bartlett Springs fault system, 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 2617 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 17 km (11 mi) from the epicentre. In Ukiah, 33 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.

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

How big was it?

This earthquake released about 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 31,000 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 · 36 km S 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 39.4382, -123.1087. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 29 km (18 mi) W earthquakes near Mendocino County
Lake County, CA 48 km (30 mi) SE earthquakes near Lake County
Glenn County, CA 63 km (39 mi) ENE earthquakes near Glenn County
Colusa County, CA 80 km (50 mi) ESE earthquakes near Colusa County
Sonoma County, CA 103 km (64 mi) S earthquakes near Sonoma County
Tehama County, CA 107 km (67 mi) NE earthquakes near Tehama County

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

Aftershocks so far

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

  1. 1.8 2km WNW of Redwood Valley, CA
  2. 2.9 15km N of Lake Pillsbury, CA
  3. 2.1 2km NNW of Talmage, CA
  4. 1.7 14km SE of Laytonville, CA
  5. 1.8 12km WNW of Redwood Valley, CA
  6. 1.9 12km WNW of Redwood Valley, CA
  7. 2.1 13km SSW of Laytonville, CA
  8. 1.6 13km SSW of Laytonville, CA
  9. 1.6 12km WNW of Redwood Valley, CA
  10. 2.3 2km NNW of Talmage, CA
  11. 2.7 2km NNW of Talmage, CA
  12. 1.6 6km SW of Upper Lake, CA
  13. 1.7 8km ENE of Covelo, CA
  14. 1.9 19km NNW of Alder Springs, CA
  15. 1.8 20km NNW of Alder Springs, 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.