QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

3 km S of Fontana, CA

· 4.2 km deep · released about 94 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 53 kmLos Angeles County 75 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
4.2 km below the surface
Felt
19 reports · strongest reported intensity IV
Nearest
Orange County, 53 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 731 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 19 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 34.0747, -117.4558. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 53 km (33 mi) NNE of here earthquakes near Orange County
Los Angeles County, CA 75 km (47 mi) E of here earthquakes near Los Angeles County
San Diego County, CA 133 km (82 mi) NNW of here earthquakes near San Diego County
San Bernardino County, CA 146 km (90 mi) SW of here earthquakes near San Bernardino County

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

Aftershocks so far

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

  1. 1.8 4 km ENE of Fontana, CA
  2. 1.8 8 km SSE of Redlands, CA
  3. 1.6 2 km N of Orange, CA
  4. 1.6 4 km WSW of Yucaipa, CA
  5. 1.6 2 km WNW of Villa Park, CA
  6. 1.7 4 km WSW of Redlands, CA
  7. 1.6 4 km WSW of Redlands, CA
  8. 2.3 4 km WSW of Redlands, CA
  9. 1.6 4 km WSW of Redlands, CA
  10. 1.8 7 km ENE of Lake Arrowhead, CA
  11. 1.6 4 km SSW of Calimesa, CA
  12. 1.8 1 km ENE of Valinda, CA
  13. 1.7 8 km SSE of Home Gardens, CA
  14. 1.5 3 km WNW of Calimesa, CA
  15. 1.6 2 km NNW of Orange, 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 1,200 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.