Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Lewiston, CA
No earthquake was likely felt in Lewiston in the 24 hours to 11:03 pm PST (07:03 UTC). The last one was M 4.4, 93 km (58 mi) SW, at 3:21 pm PDT on 5 August 2026, estimated intensity II (weak) in town; 122 felt reports to USGS. Every earthquake near Lewiston
This page: a magnitude 1.6 earthquake was recorded 10 km (6 mi) north-northeast of Lewiston, CA, at 5:49 am PDT on 21 September 2018 (12:49 UTC), 20 km deep.
USGS: 10km NNE of Lewiston, CA
41 km (26 mi) NW of Redding, CA · 140 km (87 mi) NW of Chico, CA
- When
- 5:49 am PDT on 21 September 2018 ()
- Where
- 10 km (6 mi) north-northeast of Lewiston, CA · earthquakes near Lewiston
- Magnitude
- M 1.6 (md)
- Depth
- 20 km below the surface
- Felt
- no reports yet
- Nearest
- Trinity County, 34 km WSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2970 days ago
Earthquake alerts for Lewiston, CA
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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 Lewiston, 10 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.
Earthquakes near other towns within 30 km: Weaverville.
How big was it?
This earthquake released about 8.1 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 1,300,000× 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 8.1 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:
- 5.1 7km NW of Redding, CA · 35 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 40.7933, -122.7602. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Trinity County, CA | 34 km (21 mi) | WSW | earthquakes near Trinity County |
| Shasta County, CA | 60 km (38 mi) | E | earthquakes near Shasta County |
| Tehama County, CA | 87 km (54 mi) | SSE | earthquakes near Tehama County |
| Siskiyou County, CA | 90 km (56 mi) | NNE | earthquakes near Siskiyou County |
| Humboldt County, CA | 99 km (61 mi) | W | earthquakes near Humboldt County |
| Del Norte County, CA | 147 km (92 mi) | NW | earthquakes near Del Norte County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
48 earthquakes have been recorded within 50 km since this one.
- 2.1 4km W of Bella Vista, CA
- 1.6 5km ESE of Redding, CA
- 1.7 4km SE of Redding, CA
- 1.6 1km N of Shasta, CA
- 1.7 9km NE of Shasta Lake, CA
- 2.4 26km WNW of Montgomery Creek, CA
- 2.0 27km N of Shasta Lake, CA
- 1.7 9km NE of Shasta Lake, CA
- 1.7 11km NE of Shasta Lake, CA
- 1.7 2km NW of Shasta Lake, CA
- 1.7 6km NE of Shasta Lake, CA
- 1.5 9km NNE of Shasta Lake, CA
- 1.6 3km SW of Shasta Lake, CA
- 2.6 21km NW of Weaverville, CA
- 1.6 14km NNE of French Gulch, 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.