QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

4km N of Norco, CA

· 5.0 km deep · released about 94 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 38 kmLos Angeles County 70 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 2.3 (ml)
Depth
5.0 km below the surface
Felt
20 reports · strongest reported intensity IV
Nearest
Orange County, 38 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2368 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 20 people have reported feeling it to USGS.

How big was it?

This earthquake released about 94 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 160,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 110,000× the energy of this one
  3. Around the size people start to feel M 3.0 10× the energy of this one
  4. This earthquake M 2.3 about 94 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 33.9635, -117.5515. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 38 km (24 mi) NNE of here earthquakes near Orange County
Los Angeles County, CA 70 km (44 mi) ESE of here earthquakes near Los Angeles County
San Diego County, CA 127 km (79 mi) NW of here earthquakes near San Diego 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. 1.5 5km SE of Loma Linda, CA
  2. 1.7 2km NNE of Colton, CA
  3. 3.0 6km NE of Fontana, CA
  4. 2.1 4km ESE of Lytle Creek, CA
  5. 3.2 4km ESE of Lytle Creek, CA
  6. 1.8 4km NNE of Fontana, CA
  7. 1.8 6km SSE of Loma Linda, CA
  8. 1.7 8km SSE of Home Gardens, CA
  9. 1.6 12km NE of Trabuco Canyon, CA
  10. 1.8 1km E of South Whittier, CA
  11. 1.6 8km N of Fontana, CA
  12. 2.5 2km NE of Redlands, CA
  13. 1.9 2km NE of Redlands, CA
  14. 1.8 8km ESE of Wrightwood, CA
  15. 1.6 2km NE of Redlands, 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.