QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

3km NE of Placentia, CA

· 5.2 km deep · released about 11 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 25 kmLos Angeles County 51 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 1.7 (ml)
Depth
5.2 km below the surface
Felt
no reports yet
Nearest
Orange County, 25 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1921 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 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 970,000× the energy of this one
  3. Around the size people start to feel M 3.0 86× the energy of this one
  4. This earthquake M 1.7 about 11 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 33.8932, -117.8498. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 25 km (16 mi) NNW of here earthquakes near Orange County
Los Angeles County, CA 51 km (32 mi) SE of here earthquakes near Los Angeles County
Ventura County, CA 129 km (80 mi) ESE of here earthquakes near Ventura County
San Diego County, CA 139 km (86 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

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

  1. 2.6 1km ESE of Carson, CA
  2. 1.6 4km SE of Rancho Cucamonga, CA
  3. 1.6 2km E of Carson, CA
  4. 2.5 0km ESE of Carson, CA
  5. 2.0 2km SE of Carson, CA
  6. 2.8 2km ESE of Carson, CA
  7. 4.3 2km E of Carson, CA
  8. 1.7 5km SSE of Home Gardens, CA
  9. 2.6 3km NNW of La Verne, CA
  10. 2.1 5km SSE of Home Gardens, CA
  11. 1.6 5km NNE of Fontana, CA
  12. 2.6 5km NNE of Fontana, CA
  13. 1.6 4km NE of Whittier, CA
  14. 1.7 2km NNW of Inglewood, CA
  15. 1.9 4km SE of Home Gardens, 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 4.5 on 2020-09-19 — it released about 18,000 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.