Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Chester, CA
No earthquake was likely felt in Chester in the 24 hours to 8:06 pm PST (04:06 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 49 km (30 mi) north-northeast of Chester, CA, at 7:16 pm PDT on 25 September 2018 (02:16 UTC), 12 km deep.
USGS: 42km SE of Fall River Mills, CA
- When
- 7:16 pm PDT on 25 September 2018 ()
- Where
- 49 km (30 mi) north-northeast of Chester, CA · earthquakes near Chester
- Magnitude
- M 1.6 (md)
- Depth
- 12 km below the surface
- Felt
- no reports yet
- Nearest
- Lassen County, 40 km E
- Nearest mapped fault
- McArthur fault, 15 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 2971 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 it was probably too small to be felt, even directly above it. In Chester, 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 7.8 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 1,900,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
- Around the size people start to feel M 3.0 120× the energy of this one
- This earthquake M 1.6 about 7.8 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 one earthquake of M5 or more within 50 km:
- 5.5 15 km NE of Mineral, California · 44 km SW 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 40.7325, -121.0968. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lassen County, CA | 40 km (25 mi) | E | earthquakes near Lassen County |
| Shasta County, CA | 80 km (50 mi) | W | earthquakes near Shasta County |
| Plumas County, CA | 85 km (53 mi) | SSE | earthquakes near Plumas County |
| Modoc County, CA | 101 km (63 mi) | NNE | earthquakes near Modoc County |
| Tehama County, CA | 117 km (73 mi) | SW | earthquakes near Tehama County |
| Butte County, CA | 126 km (78 mi) | SSW | earthquakes near Butte County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
47 earthquakes have been recorded within 50 km since this one.
- 1.6 12km ESE of Viola, CA
- 2.2 12km ESE of Viola, CA
- 1.6 22km NE of Viola, CA
- 2.0 14km NNE of Mineral, CA
- 1.6 30km NNE of Hamilton Branch, CA
- 1.8 20km WNW of Susanville, CA
- 2.0 45km SE of Fall River Mills, CA
- 2.4 44km SE of Fall River Mills, CA
- 2.0 22km E of McArthur, CA
- 1.6 23km SE of Burney, CA
- 1.8 28km NNE of Susanville, CA
- 1.7 15km NNW of Chester, CA
- 2.3 15km NNW of Susanville, CA
- 1.6 10km SSE of Burney, CA
- 1.8 20km SE of Burney, 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.