QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

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 2.5 earthquake was recorded 18 km (11 mi) north-northeast of Ukiah, CA, at 10:15 am PST on 6 February 2017 (18:15 UTC), 1.1 km deep.

USGS: 3 km SSE of Potter Valley, California

10:15 am PST, Feb 6, 2017 · · 1.1 km deep · released about 180 lb of TNT

10 km30 km60 km120 km N Mendocino County 33 kmLake County 37 kmGlenn County 69 kmColusa County 75 kmSonoma County 87 kmNapa County 110 kmTehama County 119 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
10:15 am PST on 6 February 2017 ()
Where
18 km (11 mi) north-northeast of Ukiah, CA · earthquakes near Ukiah
Magnitude
M 2.5 (md)
Depth
1.1 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 33 km WNW
Nearest mapped fault
Maacama fault, 10 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 3564 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 22 km (14 mi) from the epicentre. In Ukiah, 18 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 18 km, intensity II · Upper Lake 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 180 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 86,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 61,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.4× the energy of this one
  4. This earthquake M 2.5 about 180 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 7,400 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 · 20 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 39.2923, -123.1005. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 33 km (21 mi) WNW earthquakes near Mendocino County
Lake County, CA 37 km (23 mi) ESE earthquakes near Lake County
Glenn County, CA 69 km (43 mi) ENE earthquakes near Glenn County
Colusa County, CA 75 km (47 mi) E earthquakes near Colusa County
Sonoma County, CA 87 km (54 mi) S earthquakes near Sonoma County
Napa County, CA 110 km (68 mi) SE earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.6 near the coast of Northern California
  2. 1.8 18 km NE of Upper Lake, California
  3. 2.8 19 km NNE of Upper Lake, California
  4. 1.6 2 km SSE of Lakeport, California
  5. 1.6 18 km NE of Upper Lake, California
  6. 1.6 2 km NW of Redwood Valley, California
  7. 1.6 13 km WSW of Elk Creek, California
  8. 1.6 6 km E of Redwood Valley, California
  9. 1.8 16 km NNE of Nice, California
  10. 1.6 9 km SW of Kelseyville, California
  11. 2.0 18 km NE of Upper Lake, California
  12. 1.5 19 km NE of Upper Lake, California
  13. 2.3 13 km SSE of Laytonville, California
  14. 1.7 9 km N of Philo, California
  15. 1.7 18 km NNE of Upper Lake, California

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.