QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

4km SW of Fontana, CA

· 3.3 km deep · released about 610 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 51 kmLos Angeles County 72 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 2.9 (ml)
Depth
3.3 km below the surface
Felt
175 reports · strongest reported intensity IV
Nearest
Orange County, 51 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2736 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 175 people have reported feeling it to USGS.

How big was it?

This earthquake released about 610 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 25,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 18,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.6× the energy of this one
  4. This earthquake M 2.9 about 610 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 34.0713, -117.4908. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 51 km (32 mi) NNE of here earthquakes near Orange County
Los Angeles County, CA 72 km (45 mi) E of here earthquakes near Los Angeles County
San Diego County, CA 134 km (83 mi) NNW 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

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

  1. 1.9 8km SSE of Home Gardens, CA
  2. 1.8 4km NNW of Glen Avon, CA
  3. 1.6 4km NW of Glen Avon, CA
  4. 1.8 4km NNW of Glen Avon, CA
  5. 2.1 7km SSE of Loma Linda, CA
  6. 1.6 4km NW of Glen Avon, CA
  7. 1.8 4km NW of Glen Avon, CA
  8. 1.8 4km SE of Home Gardens, CA
  9. 2.6 6km ENE of North Tustin, CA
  10. 1.6 6km ENE of North Tustin, CA
  11. 1.6 7km NW of Glen Avon, CA
  12. 1.5 1km ESE of Loma Linda, CA
  13. 2.1 4km ENE of Brea, CA
  14. 1.6 2km NNW of Valinda, CA
  15. 2.2 4km NW of Beaumont, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.4 on 2018-08-29 — it released about 180 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.