QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

Earthquake near Ukiah, CA

No earthquake was likely felt in Ukiah in the 24 hours to 8:21 am PST (16:21 UTC). The last one was M 1.5, 5 km (3 mi) E, at 3:26 am PST on 12 November 2026, estimated intensity II (weak) in town. Every earthquake near Ukiah

This page: a magnitude 2.5 earthquake was recorded 25 km (15 mi) north-northeast of Ukiah, CA, at 7:14 pm PDT on 8 July 2019 (02:14 UTC), 7.7 km deep. 19 people have reported feeling it to USGS.

USGS: 11km SW of Lake Pillsbury, CA

7:14 pm PDT, Jul 8, 2019 · · 7.7 km deep · released about 140 lb of TNT

10 km30 km60 km120 km N Mendocino County 34 kmLake County 38 kmGlenn County 64 kmColusa County 73 kmSonoma County 92 kmTehama County 112 kmNapa County 113 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
7:14 pm PDT on 8 July 2019 ()
Where
25 km (15 mi) north-northeast of Ukiah, CA · earthquakes near Ukiah
Magnitude
M 2.5 (md)
Depth
7.7 km below the surface
Felt
19 reports · strongest reported intensity IV
Nearest
Mendocino County, 34 km WNW
Nearest mapped fault
Bartlett Springs fault system, 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 2682 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 20 km (12 mi) from the epicentre. In Ukiah, 25 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, Upper Lake, Talmage, Willits, Brooktrails.

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 3.5 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 75,000× the energy of this one
  3. Around the size people start to feel M 3.0 6.7× the energy of this one
  4. This earthquake M 2.5 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 9,100 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 · 25 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 39.3437, -123.0617. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 34 km (21 mi) WNW earthquakes near Mendocino County
Lake County, CA 38 km (23 mi) SE earthquakes near Lake County
Glenn County, CA 64 km (39 mi) ENE earthquakes near Glenn County
Colusa County, CA 73 km (46 mi) ESE earthquakes near Colusa County
Sonoma County, CA 92 km (57 mi) S earthquakes near Sonoma County
Tehama County, CA 112 km (70 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 14km NNE of Brooktrails, CA
  2. 1.6 13km WNW of Lake Pillsbury, CA
  3. 2.3 5km S of Talmage, CA
  4. 1.9 3km SSW of Redwood Valley, CA
  5. 1.6 14km WNW of Lake Pillsbury, CA
  6. 2.5 4km S of Redwood Valley, CA
  7. 2.6 16km NE of Brooktrails, CA
  8. 1.6 5km NE of Ukiah, CA
  9. 2.1 13km WNW of Lake Pillsbury, CA
  10. 1.6 14km WNW of Lake Pillsbury, CA
  11. 1.6 13km WNW of Lake Pillsbury, CA
  12. 1.8 8km N of Lake Pillsbury, CA
  13. 1.9 1km SSW of Redwood Valley, CA
  14. 1.8 4km NE of Talmage, CA
  15. 1.6 1km ENE of Lake Pillsbury, 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.