QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Chester, CA

No earthquake was likely felt in Chester in the 24 hours to 4:08 pm PST (00:08 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 1.7 earthquake was recorded 25 km (15 mi) west of Chester, CA, at 1:18 am PDT on 22 July 2024 (08:18 UTC), 12 km deep.

USGS: 7 km SSE of Mineral, CA

66 km (41 mi) NNE of Chico, CA

1:18 am PDT, Jul 22, 2024 · · 12 km deep · released about 12 lb of TNT

10 km30 km60 km120 km N Tehama County 64 kmShasta County 67 kmPlumas County 69 kmButte County 72 kmLassen County 89 kmGlenn County 109 kmYuba County 116 kmSierra County 118 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
1:18 am PDT on 22 July 2024 ()
Where
25 km (15 mi) west of Chester, CA · earthquakes near Chester
Magnitude
M 1.7 (md)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Tehama County, 64 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 843 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 5 km (3 mi) from the epicentre. In Chester, 25 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 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 900,000× the energy of this one
  3. Around the size people start to feel M 3.0 80× the energy of this one
  4. This earthquake M 1.7 about 12 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 420,000 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 · 41 km ESE of this epicentre
  2. 5.5 15 km NE of Mineral, California · 16 km NNE 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 40.3083, -121.5213. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Tehama County, CA 64 km (40 mi) WSW earthquakes near Tehama County
Shasta County, CA 67 km (42 mi) NW earthquakes near Shasta County
Plumas County, CA 69 km (43 mi) ESE earthquakes near Plumas County
Butte County, CA 72 km (45 mi) S earthquakes near Butte County
Lassen County, CA 89 km (55 mi) ENE earthquakes near Lassen County
Glenn County, CA 109 km (67 mi) SW earthquakes near Glenn County

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

Aftershocks so far

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

  1. 1.9 1 km NE of Almanor, CA
  2. 2.4 2 km N of Almanor, CA
  3. 1.7 1 km NNE of Almanor, CA
  4. 2.3 2 km of Almanor, CA
  5. 1.9 3 km NE of Almanor, CA
  6. 2.2 9 km NNW of Shingletown, CA
  7. 2.4 10 km WSW of Almanor, CA
  8. 1.9 10 km WSW of Almanor, CA
  9. 2.0 11 km WSW of Almanor, CA
  10. 1.9 2 km of Almanor, CA
  11. 2.2 2 km NNE of Almanor, CA
  12. 2.4 2 km NE of Prattville, CA
  13. 2.6 1 km NNW of Canyondam, CA
  14. 2.8 2 km NNW of Canyondam, CA
  15. 1.6 8 km NNE of Viola, 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.