QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

Earthquake near Westwood, CA

No earthquake was likely felt in Westwood in the 24 hours to 6:47 am PST (14:47 UTC). The last one was M 2.1, 12 km (7 mi) SSW, at 8:09 am PDT on 29 October 2026, estimated intensity II (weak) in town. Every earthquake near Westwood

This page: a magnitude 1.8 earthquake was recorded 13 km (8 mi) south-southwest of Westwood, CA, at 7:10 pm PST on 1 January 2025 (03:10 UTC), 8.6 km deep. 1 person has reported feeling it to USGS.

USGS: 4 km N of Canyondam, CA

7:10 pm PST, Jan 1, 2025 · · 8.6 km deep · released about 16 lb of TNT

10 km30 km60 km120 km N Plumas County 32 kmLassen County 69 kmButte County 75 kmSierra County 84 kmTehama County 99 kmShasta County 103 kmNevada County 104 kmYuba County 106 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
7:10 pm PST on 1 January 2025 ()
Where
13 km (8 mi) south-southwest of Westwood, CA · earthquakes near Westwood
Magnitude
M 1.8 (md)
Depth
8.6 km below the surface
Felt
1 report
Nearest
Plumas County, 32 km SE
Nearest mapped fault
Almanor fault, under 1 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 668 days ago

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 11 km (7 mi) from the epicentre. In Westwood, 13 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: Greenville, Chester.

How big was it?

This earthquake released about 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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 310,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.7 2 km NNE of Canyondam, California · 2 km SE of this epicentre
  2. 5.5 15 km NE of Mineral, California · 43 km NW 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 40.2037, -121.0762. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Plumas County, CA 32 km (20 mi) SE earthquakes near Plumas County
Lassen County, CA 69 km (43 mi) NE earthquakes near Lassen County
Butte County, CA 75 km (47 mi) SW earthquakes near Butte County
Sierra County, CA 84 km (52 mi) SE earthquakes near Sierra County
Tehama County, CA 99 km (61 mi) W earthquakes near Tehama County
Shasta County, CA 103 km (64 mi) NW earthquakes near Shasta County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

56 earthquakes have been recorded within 50 km since this one.

  1. 1.8 13 km NNE of Mineral, CA
  2. 2.3 5 km WNW of Chester, CA
  3. 2.2 11 km NE of Cromberg, CA
  4. 1.6 5 km WNW of Chester, CA
  5. 1.9 3 km NE of Prattville, CA
  6. 2.1 3 km NE of Prattville, CA
  7. 2.6 3 km NNE of Prattville, CA
  8. 1.6 2 km NNE of Prattville, CA
  9. 1.9 2 km ENE of Almanor, CA
  10. 1.5 11 km NNE of Little Grass Valley, California
  11. 1.8 4 km N of Canyondam, CA
  12. 1.8 0 km SSE of Almanor, CA
  13. 1.9 1 km NNW of Almanor, CA
  14. 2.1 4 km NW of Almanor, CA
  15. 1.7 11 km ESE of Mineral, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.