QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

4km SE of Ontario, CA

· 4.1 km deep · released about 1,300 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 43 kmLos Angeles County 64 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 3.1 (ml)
Depth
4.1 km below the surface
Felt
539 reports · strongest reported intensity IV
Measured shaking
intensity V (ShakeMap)
Nearest
Orange County, 43 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2995 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 539 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 260,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 12,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 8,200× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× more

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 34.0317, -117.5930. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 43 km (27 mi) NNE of here earthquakes near Orange County
Los Angeles County, CA 64 km (40 mi) ESE of here earthquakes near Los Angeles County
San Diego County, CA 135 km (84 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

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

  1. 1.6 2km N of Colton, CA
  2. 1.6 4km SSE of Home Gardens, CA
  3. 2.0 5km SSW of Lytle Creek, CA
  4. 1.9 13km NE of Trabuco Canyon, CA
  5. 1.6 3km S of Mentone, CA
  6. 1.6 7km SSW of Lytle Creek, CA
  7. 1.7 6km NNE of Moreno Valley, CA
  8. 1.8 13km SSW of Wrightwood, CA
  9. 1.7 3km SE of Mentone, CA
  10. 1.5 3km SE of Mentone, CA
  11. 1.5 5km SSE of Home Gardens, CA
  12. 1.5 1km NE of Lytle Creek, CA
  13. 1.5 2km WSW of Devore, CA
  14. 2.6 3km ESE of Loma Linda, CA
  15. 1.5 3km ESE of Loma Linda, 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.