Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Chester, CA
No earthquake was likely felt in Chester in the 24 hours to 3:50 pm PST (23:50 UTC). The last one was M 2.1, 17 km (11 mi) SE, at 8:09 am PDT on 29 October 2026, estimated intensity II (weak) in town. Every earthquake near Chester
This page: a magnitude 1.6 earthquake was recorded 30 km (19 mi) northwest of Chester, CA, at 3:20 am PDT on 26 June 2021 (10:20 UTC), 2.7 km deep.
USGS: 14km NNE of Mineral, CA
83 km (52 mi) NNE of Chico, CA
- When
- 3:20 am PDT on 26 June 2021 ()
- Where
- 30 km (19 mi) northwest of Chester, CA · earthquakes near Chester
- Magnitude
- M 1.6 (md)
- Depth
- 2.7 km below the surface
- Felt
- no reports yet
- Nearest
- Shasta County, 55 km NW
- Nearest mapped fault
- Hat Creek fault, 21 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 1965 days ago
Earthquake alerts for Chester, CA
Get a notification in this browser when USGS records an earthquake near Chester, 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 10 km (6 mi) from the epicentre. In Chester, 30 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 6.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,300,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
- Around the size people start to feel M 3.0 140× the energy of this one
- This earthquake M 1.6 about 6.6 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.7 2 km NNE of Canyondam, California · 50 km SE of this epicentre
- 5.5 15 km NE of Mineral, California · 5 km ESE 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 40.4728, -121.5137. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Shasta County, CA | 55 km (34 mi) | NW | earthquakes near Shasta County |
| Tehama County, CA | 72 km (45 mi) | WSW | earthquakes near Tehama County |
| Plumas County, CA | 79 km (49 mi) | SE | earthquakes near Plumas County |
| Lassen County, CA | 80 km (50 mi) | ENE | earthquakes near Lassen County |
| Butte County, CA | 90 km (56 mi) | S | earthquakes near Butte County |
| Glenn County, CA | 123 km (76 mi) | SW | earthquakes near Glenn 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.
- 2.1 4km NNW of Canyondam, CA
- 1.8 5km E of Chester, CA
- 1.7 4km ESE of Chester, CA
- 2.3 24km NNE of Forest Ranch, CA
- 2.2 8km W of Chester, CA
- 2.9 12km SE of Mineral, CA
- 2.5 3km E of Prattville, CA
- 2.3 3km ENE of Prattville, CA
- 1.6 7km WSW of Shingletown, CA
- 2.3 9km WSW of Shingletown, CA
- 2.4 21km SSE of Mineral, CA
- 2.2 21km NE of Viola, CA
- 1.6 2km E of Prattville, CA
- 2.8 2km ENE of Prattville, CA
- 2.5 2km ENE of Prattville, 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.