Earthquake · reviewed by a seismologist
M 3.9mw
Earthquake near Willows, CA
No earthquake was likely felt in Willows in the 24 hours to 5:53 am PST (13:53 UTC). The last one was M 4.0, 65 km (40 mi) W, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Willows
This page: a magnitude 3.9 earthquake was recorded 15 km (9 mi) east of Willows, CA, at 6:44 am PST on 27 December 2020 (14:44 UTC), 26 km deep. 624 people have reported feeling it to USGS.
USGS: 15km E of Willows, CA
33 km (20 mi) SSW of Chico, CA · 115 km (71 mi) NNW of Sacramento, CA
- When
- 6:44 am PST on 27 December 2020 ()
- Where
- 15 km (9 mi) east of Willows, CA · earthquakes near Willows
- Magnitude
- M 3.9 (mw)
- Depth
- 26 km below the surface
- Felt
- 624 reports · strongest reported intensity IV
- Measured shaking
- intensity VI (ShakeMap)
- Nearest
- Glenn County, 35 km WNW
- Nearest mapped fault
- Great Valley thrust fault system, 24 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 2032 days ago
Earthquake alerts for Willows, CA
Get a notification in this browser when USGS records an earthquake near Willows, 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 83 km (52 mi) from the epicentre. In Willows, 15 km away, the estimate is intensity III (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.
Likely felt in: Willows 15 km, intensity III · Hamilton City 26 km, intensity III · Chico 29 km, intensity III · Paradise 44 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 9.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 18,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 810× the energy of this one
- Magna, Utah 2020 M 5.7 580× the energy of this one
- This earthquake M 3.9 about 9.3 tons of TNT
- Around the size people start to feel M 3.0 this one released 19× more
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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 5.7 The 1975 Oroville, California Earthquake · 41 km ESE of this epicentre
- 5.2 4 km E of Palermo, California · 46 km E of this epicentre
- 5.1 5 km ENE of Palermo, California · 47 km E 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 39.5058, -122.0177. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Glenn County, CA | 35 km (22 mi) | WNW | earthquakes near Glenn County |
| Butte County, CA | 40 km (25 mi) | ENE | earthquakes near Butte County |
| Colusa County, CA | 41 km (26 mi) | SSW | earthquakes near Colusa County |
| Sutter County, CA | 59 km (37 mi) | SSE | earthquakes near Sutter County |
| Yuba County, CA | 64 km (39 mi) | ESE | earthquakes near Yuba County |
| Tehama County, CA | 71 km (44 mi) | NNW | earthquakes near Tehama County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 2.2 9 km WSW of Williams, CA
- 2.4 18 km E of Willows, CA
- 2.6 15 km ENE of Willows, CA
- 2.1 12km W of Williams, CA
- 2.3 13km WSW of Williams, CA
- 2.1 18km E of Willows, CA
- 2.2 18km E of Willows, CA
- 2.1 8km WSW of Durham, CA
- 2.3 14km S of Hamilton City, CA
- 2.4 10km WSW of Williams, CA
- 1.9 3km NW of Chico, CA
- 2.1 10km N of Oroville, CA
- 2.7 2km NW of Chico, CA
- 2.1 13km SSE of Willows, CA
- 4.2 5km S of Oroville East, 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.