QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

3km ENE of Brea, CA

· 8.2 km deep · released about 750 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 29 kmLos Angeles County 47 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
8.2 km below the surface
Felt
646 reports · strongest reported intensity III
Measured shaking
intensity III (ShakeMap)
Nearest
Orange County, 29 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 713 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 646 people have reported feeling it to USGS.

How big was it?

This earthquake released about 750 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 20,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 14,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.3× the energy of this one
  4. This earthquake M 2.9 about 750 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 33.9268, -117.8748. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 29 km (18 mi) NNW of here earthquakes near Orange County
Los Angeles County, CA 47 km (29 mi) SE of here earthquakes near Los Angeles County
Ventura County, CA 125 km (78 mi) ESE of here earthquakes near Ventura County
San Diego County, CA 143 km (89 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

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

  1. 1.6 3km SE of Home Gardens, CA
  2. 1.6 4km N of Norco, CA
  3. 1.5 3km W of Highland Park, CA
  4. 1.6 0km S of View Park-Windsor Hills, CA
  5. 1.6 8km SSE of Home Gardens, CA
  6. 1.6 0km S of View Park-Windsor Hills, CA
  7. 1.6 1km SE of View Park-Windsor Hills, CA
  8. 1.6 0km SE of View Park-Windsor Hills, CA
  9. 3.7 1km S of View Park-Windsor Hills, CA
  10. 2.1 1km S of View Park-Windsor Hills, CA
  11. 1.6 2km NNE of Laguna Niguel, CA
  12. 1.7 4km E of Rancho Cucamonga, CA
  13. 1.9 3km NNW of Walnut, CA
  14. 1.7 5km SSE of Home Gardens, CA
  15. 1.5 2km SSE of View Park-Windsor Hills, 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 150 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.