QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

9km SSE of Challenge-Brownsville, CA

· 16 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Yuba County 17 kmNevada County 41 kmButte County 44 kmSutter County 57 kmPlacer County 57 kmSierra County 64 kmPlumas County 75 kmColusa County 90 kmEl Dorado County 90 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 (md)
Depth
16 km below the surface
Felt
no reports yet
Nearest
Yuba County, 17 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2260 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 14 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× the energy of this one
  4. This earthquake M 1.8 about 14 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 39.3897, -121.2297. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Yuba County, CA 17 km (10 mi) NE of here earthquakes near Yuba County
Nevada County, CA 41 km (25 mi) WNW of here earthquakes near Nevada County
Butte County, CA 44 km (28 mi) SE of here earthquakes near Butte County
Sutter County, CA 57 km (35 mi) NE of here earthquakes near Sutter County
Placer County, CA 57 km (35 mi) NW of here earthquakes near Placer County
Sierra County, CA 64 km (40 mi) WSW of here earthquakes near Sierra County

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

Aftershocks so far

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

  1. 2.0 6 km E of Challenge-Brownsville, CA
  2. 2.1 8 km WNW of La Porte, CA
  3. 2.1 7 km ESE of Challenge-Brownsville, CA
  4. 1.9 5 km WSW of Concow, CA
  5. 1.8 8 km NNE of Oroville East, CA
  6. 1.7 8 km NNE of Oroville East, CA
  7. 2.1 12 km W of La Porte, CA
  8. 1.6 Northern California
  9. 2.1 10km N of Oroville, CA
  10. 2.0 5km SSE of Oroville East, CA
  11. 2.3 10km WNW of Little Grass Valley, CA
  12. 4.2 5km S of Oroville East, CA
  13. 2.2 9km E of Little Grass Valley, CA
  14. 1.8 10km N of Oroville, CA
  15. 2.0 10km N of Oroville, 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.