QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

3km NW of Fontana, CA

· 17 km deep · released about 460 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 57 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 2.8 (ml)
Depth
17 km below the surface
Felt
17 reports · strongest reported intensity III
Nearest
Orange County, 57 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2969 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 17 people have reported feeling it to USGS.

How big was it?

This earthquake released about 460 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 33,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 23,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.1× the energy of this one
  4. This earthquake M 2.8 about 460 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 34.1215, -117.4808. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 57 km (35 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 Bernardino County, CA 144 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

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

  1. 1.5 7km SSE of Home Gardens, CA
  2. 3.0 9km WSW of Wrightwood, CA
  3. 1.6 12km SSE of Corona, CA
  4. 1.7 7km SSW of Redlands, CA
  5. 1.9 4km N of La Verne, CA
  6. 2.1 7km WSW of Calimesa, CA
  7. 1.7 4km ENE of Calimesa, CA
  8. 3.5 4km ENE of Calimesa, CA
  9. 2.1 9km ENE of North Tustin, CA
  10. 1.7 9km E of Running Springs, CA
  11. 3.6 4km ENE of Calimesa, CA
  12. 1.8 8km E of Yorba Linda, CA
  13. 2.1 7km W of Calimesa, CA
  14. 1.9 2km WNW of Orange, CA
  15. 2.0 2km 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.