QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

4 km NW of Spring Garden, California

· 7.9 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Plumas County 8 kmSierra County 46 kmNevada County 70 kmButte County 73 kmYuba County 85 kmLassen County 90 kmPlacer County 96 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
Magnitude
M 1.8 (ml)
Depth
7.9 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Plumas County, 8 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1143 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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.

Where

Epicentre 39.9225, -120.8217. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Plumas County, CA 8 km (5 mi) S of here earthquakes near Plumas County
Sierra County, CA 46 km (29 mi) NNW of here earthquakes near Sierra County
Nevada County, CA 70 km (43 mi) N of here earthquakes near Nevada County
Butte County, CA 73 km (45 mi) ENE of here earthquakes near Butte County
Yuba County, CA 85 km (53 mi) NNE of here earthquakes near Yuba County
Lassen County, CA 90 km (56 mi) S of here earthquakes near Lassen County

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

Aftershocks so far

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

  1. 1.9 1 km N of Prattville, CA
  2. 2.1 0 km N of Valley Ranch, California
  3. 1.5 0 km ENE of Valley Ranch, California
  4. 1.6 0 km NNE of Clio, California
  5. 1.7 1 km E of Valley Ranch, California
  6. 2.1 4 km NNE of Prattville, CA
  7. 1.7 Northern California
  8. 2.8 0 km NNE of Valley Ranch, CA
  9. 1.6 0 km SSE of Valley Ranch, California
  10. 1.9 5 km NW of Almanor, CA
  11. 2.4 1 km NE of Valley Ranch, CA
  12. 1.6 0 km SSE of Valley Ranch, California
  13. 1.7 0 km S of Clio, California
  14. 2.8 0 km E of Valley Ranch, CA
  15. 1.5 1 km ESE of Valley Ranch, California

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.

For this area

The largest earthquake within 50 km in our catalogue was M 5.5 on 2023-05-11 — it released about 330,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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