Earthquake · reviewed by a seismologist
M 2.0md
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 2.0 earthquake was recorded 41 km (26 mi) north-northeast of Ukiah, CA, at 9:01 am PST on 21 December 2017 (17:01 UTC), less than 1 km deep.
USGS: 17km NW of Lake Pillsbury, CA
- When
- 9:01 am PST on 21 December 2017 ()
- Where
- 41 km (26 mi) north-northeast of Ukiah, CA · earthquakes near Ukiah
- Magnitude
- M 2.0 (md)
- Depth
- 0.4 km below the surface
- Felt
- no reports yet
- Nearest
- Mendocino County, 31 km WSW
- 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 3240 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 17 km (11 mi) from the epicentre. In Ukiah, 41 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: Willits, Brooktrails, Redwood Valley.
How big was it?
This earthquake released about 36 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 420,000× the energy of this one
- Magna, Utah 2020 M 5.7 300,000× the energy of this one
- Around the size people start to feel M 3.0 27× the energy of this one
- This earthquake M 2.0 about 36 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 36,000 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 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 39.5108, -123.1018. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mendocino County, CA | 31 km (19 mi) | WSW | earthquakes near Mendocino County |
| Lake County, CA | 54 km (34 mi) | SE | earthquakes near Lake County |
| Glenn County, CA | 61 km (38 mi) | E | earthquakes near Glenn County |
| Colusa County, CA | 83 km (52 mi) | ESE | earthquakes near Colusa County |
| Tehama County, CA | 101 km (63 mi) | NE | earthquakes near Tehama County |
| Sonoma County, CA | 111 km (69 mi) | S | earthquakes near Sonoma County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
53 earthquakes have been recorded within 50 km since this one.
- 1.5 6km SSE of Laytonville, CA
- 1.6 17km NNE of Nice, CA
- 1.8 15km ESE of Lake Pillsbury, CA
- 1.9 8km ESE of Willits, CA
- 1.8 18km SE of Lake Pillsbury, CA
- 1.7 7km ESE of Redwood Valley, CA
- 2.0 7km NW of Laytonville, CA
- 1.6 5km SW of Laytonville, CA
- 2.0 4km NE of Lake Pillsbury, CA
- 1.6 10km SSE of Lake Pillsbury, CA
- 1.7 5km E of Lake Pillsbury, CA
- 1.8 9km NNE of Laytonville, CA
- 1.6 19km NE of Upper Lake, CA
- 1.8 5km SW of Laytonville, CA
- 1.6 8km W of Upper Lake, 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.