Earthquake · reviewed by a seismologist
M 1.9md
Earthquake near Willits, CA
No earthquake was likely felt in Willits in the 24 hours to 1:35 am PST (09:35 UTC). The last one was M 1.5, 9 km (5 mi) ESE, at 10:30 pm PST on 2 November 2026, estimated intensity II (weak) in town. Every earthquake near Willits
This page: a magnitude 1.9 earthquake was recorded 49 km (31 mi) northeast of Willits, CA, at 10:11 pm PDT on 17 September 2021 (05:11 UTC), less than 1 km deep.
USGS: 13km W of Alder Springs, CA
- When
- 10:11 pm PDT on 17 September 2021 ()
- Where
- 49 km (31 mi) northeast of Willits, CA · earthquakes near Willits
- Magnitude
- M 1.9 (md)
- Depth
- 0.3 km below the surface
- Felt
- no reports yet
- Nearest
- Glenn County, 41 km E
- Nearest mapped fault
- Bartlett Springs fault system, 8 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 1878 days ago
Earthquake alerts for Willits, CA
Get a notification in this browser when USGS records an earthquake near Willits, 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 15 km (9 mi) from the epicentre. In Willits, 49 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 24 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 640,000× the energy of this one
- Magna, Utah 2020 M 5.7 450,000× the energy of this one
- Around the size people start to feel M 3.0 40× the energy of this one
- This earthquake M 1.9 about 24 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 55,000 times the energy of this one.
Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.
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 39.6593, -122.8780. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Glenn County, CA | 41 km (26 mi) | E | earthquakes near Glenn County |
| Mendocino County, CA | 55 km (34 mi) | WSW | earthquakes near Mendocino County |
| Lake County, CA | 62 km (39 mi) | S | earthquakes near Lake County |
| Tehama County, CA | 76 km (47 mi) | NE | earthquakes near Tehama County |
| Colusa County, CA | 77 km (48 mi) | SE | earthquakes near Colusa County |
| Butte County, CA | 109 km (68 mi) | E | earthquakes near Butte County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 1.8 8km NW of Redwood Valley, CA
- 1.8 5km SE of Lake Pillsbury, CA
- 1.8 2km E of Willits, CA
- 2.9 13km WNW of Alder Springs, CA
- 2.8 14km WNW of Alder Springs, CA
- 2.0 13km WNW of Alder Springs, CA
- 2.4 14km WNW of Alder Springs, CA
- 1.5 7km ENE of Brooktrails, CA
- 1.8 6km SE of Lake Pillsbury, CA
- 1.9 18km SE of Lake Pillsbury, CA
- 1.7 13km SE of Laytonville, CA
- 2.1 9km NNW of Lake Pillsbury, CA
- 1.6 7km NE of Willits, CA
- 2.0 10km NNW of Redwood Valley, CA
- 1.8 9km NNW 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.