Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Ukiah, CA
No earthquake was likely felt in Ukiah in the 24 hours to 8:51 am PST (16:51 UTC). The last one was M 4.0, 45 km (28 mi) NNE, at 5:01 am PDT on 28 October 2026, estimated intensity III (weak) in town; 14 felt reports to USGS. Every earthquake near Ukiah
This page: a magnitude 1.8 earthquake was recorded 45 km (28 mi) north-northeast of Ukiah, CA, at 3:28 am PDT on 23 August 2026 (10:28 UTC), 11 km deep.
USGS: 10 km N of Lake Pillsbury, CA
- When
- 3:28 am PDT on 23 August 2026 ()
- Where
- 45 km (28 mi) north-northeast of Ukiah, CA · earthquakes near Ukiah
- Magnitude
- M 1.8 (md)
- Depth
- 11 km below the surface
- Felt
- no reports yet
- Nearest
- Mendocino County, 43 km W
- Nearest mapped fault
- Bartlett Springs fault system, 2 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 70 days ago
Earthquake alerts for Ukiah, CA
Get a notification in this browser when USGS records an earthquake near Ukiah, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 8 km (5 mi) from the epicentre. In Ukiah, 45 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.
How big was it?
This earthquake released about 13 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 810,000× the energy of this one
- Around the size people start to feel M 3.0 72× the energy of this one
- This earthquake M 1.8 about 13 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 5.6 on 2026-06-24 — about 560,000 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.2 6 km ESE of Talmage, California · 44 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 39.4983, -122.9522. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mendocino County, CA | 43 km (27 mi) | W | earthquakes near Mendocino County |
| Lake County, CA | 47 km (29 mi) | SSE | earthquakes near Lake County |
| Glenn County, CA | 49 km (30 mi) | ENE | earthquakes near Glenn County |
| Colusa County, CA | 71 km (44 mi) | ESE | earthquakes near Colusa County |
| Tehama County, CA | 93 km (58 mi) | NE | earthquakes near Tehama County |
| Sonoma County, CA | 108 km (67 mi) | S | earthquakes near Sonoma County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
58 earthquakes have been recorded within 50 km since this one.
- 2.3 17 km SE of Lake Pillsbury, CA
- 2.0 8 km NNE of Brooktrails, CA
- 1.8 7 km NNW of Redwood Valley, CA
- 1.7 14 km N of Brooktrails, CA
- 1.7 15 km N of Brooktrails, CA
- 1.2 1 km WSW of Redwood Valley, CA
- 1.3 11 km ESE of Willits, CA
- 2.4 6 km N of Redwood Valley, CA
- 1.8 14 km NNE of Brooktrails, CA
- 1.9 8 km N of Lake Pillsbury, CA
- 1.6 9 km NW of Redwood Valley, CA
- 2.1 8 km NE of Talmage, CA
- 1.9 7 km NNW of Redwood Valley, CA
- 1.8 6 km SW of Upper Lake, CA
- 1.8 8 km N 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.