Earthquake · automatic estimate, may change
M 1.5md
Earthquake near Chester, CA
No earthquake was likely felt in Chester in the 24 hours to 9:47 pm PST (05:47 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 1.5 earthquake was recorded 12 km (8 mi) west-southwest of Chester, CA, at 8:30 am PDT on 23 September 2026 (15:30 UTC), 7.1 km deep. The magnitude and location are an automatic first estimate and may change.
USGS: 12 km WSW of Chester, CA
70 km (43 mi) NNE of Chico, CA
- When
- 8:30 am PDT on 23 September 2026 ()
- Where
- 12 km (8 mi) west-southwest of Chester, CA · earthquakes near Chester
- Magnitude
- M 1.5 (md)
- Depth
- 7.1 km below the surface
- Felt
- no reports yet
- Nearest
- Plumas County, 57 km SE
- Nearest mapped fault
- Almanor fault, 15 km from its surface trace — near is not the same as on
- Status
- Automatic — a machine’s first estimate, which may change
USGS · last changed by USGS · we first saw it 51 days ago
Earthquake alerts for Chester, CA
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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 Chester, 12 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.
How big was it?
This earthquake released about 5.9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
- Around the size people start to feel M 3.0 160× the energy of this one
- This earthquake M 1.5 about 5.9 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 5.5 on 2023-05-11 — about 840,000 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.7 2 km NNE of Canyondam, California · 29 km ESE of this epicentre
- 5.5 15 km NE of Mineral, California · 20 km NNW 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 40.2847, -121.3728. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Plumas County, CA | 57 km (35 mi) | SE | earthquakes near Plumas County |
| Butte County, CA | 72 km (44 mi) | SSW | earthquakes near Butte County |
| Tehama County, CA | 75 km (47 mi) | WSW | earthquakes near Tehama County |
| Shasta County, CA | 78 km (48 mi) | NW | earthquakes near Shasta County |
| Lassen County, CA | 80 km (49 mi) | NE | earthquakes near Lassen County |
| Sierra County, CA | 107 km (67 mi) | SE | earthquakes near Sierra County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
11 earthquakes have been recorded within 50 km since this one.
- 1.8 14 km NW of Belden, CA
- 2.1 3 km S of East Shore, CA
- 1.7 13 km SW of Chester, CA
- 2.1 2 km N of Canyondam, CA
- 2.3 10 km WNW of Caribou, CA
- 2.0 2 km NE of Almanor, CA
- 1.9 3 km NE of Almanor, CA
- 2.3 1 km NNE of Almanor, CA
- 1.9 14 km WSW of Almanor, CA
- 1.7 4 km N of Canyondam, CA
- 2.4 12 km WSW of Chester, 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.