QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

4km NNE of Fontana, CA

· 4.3 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 60 kmLos Angeles County 77 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 (ml)
Depth
4.3 km below the surface
Felt
no reports yet
Nearest
Orange County, 60 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2984 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 13 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 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 34.1292, -117.4337. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 60 km (37 mi) NNE of here earthquakes near Orange County
Los Angeles County, CA 77 km (48 mi) E of here earthquakes near Los Angeles County
San Bernardino County, CA 140 km (87 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

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

  1. 2.0 5km ENE of Ontario, CA
  2. 2.1 12km NW of Big Bear Lake, CA
  3. 2.2 5km SE of Loma Linda, CA
  4. 1.9 6km N of Moreno Valley, CA
  5. 1.9 6km E of Calimesa, CA
  6. 1.7 8km S of Hesperia, CA
  7. 1.9 4km SE of Home Gardens, CA
  8. 1.7 7km N of Running Springs, CA
  9. 1.6 6km N of Beaumont, CA
  10. 1.6 4km ENE of Calimesa, CA
  11. 1.7 10km SSW of Lucerne Valley, CA
  12. 1.6 8km ESE of North Tustin, CA
  13. 2.2 3km ENE of Calimesa, CA
  14. 2.1 1km WNW of Pomona, CA
  15. 1.8 11km ESE of Running Springs, 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.