QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

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 1.6 earthquake was recorded 41 km (25 mi) northeast of Ukiah, CA, at 7:29 pm PDT on 6 July 2018 (02:29 UTC), 12 km deep.

USGS: 7km E of Lake Pillsbury, CA

7:29 pm PDT, Jul 6, 2018 · · 12 km deep · released about 6.4 lb of TNT

10 km30 km60 km120 km N Lake County 36 kmGlenn County 46 kmMendocino County 49 kmColusa County 61 kmTehama County 97 kmSonoma County 99 kmSutter County 110 kmNapa County 111 kmButte 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
7:29 pm PDT on 6 July 2018 ()
Where
41 km (25 mi) northeast of Ukiah, CA · earthquakes near Ukiah
Magnitude
M 1.6 (md)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Lake County, 36 km SSE
Nearest mapped fault
Bartlett Springs fault system, 7 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 3050 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Ukiah, 41 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: Upper Lake.

How big was it?

This earthquake released about 6.4 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 2,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.6 about 6.4 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 200,000 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 · 38 km SSW 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 39.4132, -122.8783. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 36 km (22 mi) SSE earthquakes near Lake County
Glenn County, CA 46 km (29 mi) ENE earthquakes near Glenn County
Mendocino County, CA 49 km (30 mi) W earthquakes near Mendocino County
Colusa County, CA 61 km (38 mi) ESE earthquakes near Colusa County
Tehama County, CA 97 km (60 mi) NE earthquakes near Tehama County
Sonoma County, CA 99 km (61 mi) S earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 1.8 15km NW of Alder Springs, CA
  2. 2.0 8km NNW of Redwood Valley, CA
  3. 2.2 13km ENE of Redwood Valley, CA
  4. 1.9 3km NW of Redwood Valley, CA
  5. 1.9 17km SE of Lake Pillsbury, CA
  6. 1.9 17km ESE of Lake Pillsbury, CA
  7. 1.9 8km SSE of Lake Pillsbury, CA
  8. 1.6 7km ENE of Willits, CA
  9. 2.5 20km NNW of Alder Springs, CA
  10. 1.6 20km NNW of Alder Springs, CA
  11. 2.1 20km NNW of Alder Springs, CA
  12. 2.3 7km E of Willits, CA
  13. 1.6 7km ENE of Willits, CA
  14. 1.9 16km NE of Upper Lake, CA
  15. 1.9 7km NE of Brooktrails, 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.