QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

4km E of Brea, CA

· 9.0 km deep · released about 9.3 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 29 kmLos Angeles County 48 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
9.0 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Orange County, 29 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2791 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 2 people have reported feeling it to USGS.

How big was it?

This earthquake released about 9.3 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 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 33.9223, -117.8618. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 29 km (18 mi) NNW of here earthquakes near Orange County
Los Angeles County, CA 48 km (30 mi) SE of here earthquakes near Los Angeles County
Ventura County, CA 127 km (79 mi) ESE of here earthquakes near Ventura County
San Diego County, CA 142 km (88 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 1km NNW of Downey, CA
  2. 1.6 4km SE of Home Gardens, CA
  3. 1.7 3km ESE of Home Gardens, CA
  4. 2.2 3km WSW of Pedley, CA
  5. 1.9 5km N of Yorba Linda, CA
  6. 1.9 4km WSW of Lytle Creek, CA
  7. 1.7 8km ESE of Yorba Linda, CA
  8. 1.6 4km NNW of Mira Loma, CA
  9. 1.7 3km WNW of Inglewood, CA
  10. 1.9 3km WSW of Pedley, CA
  11. 1.7 4km SE of Home Gardens, CA
  12. 1.5 2km WNW of Willowbrook, CA
  13. 1.7 4km SE of Home Gardens, CA
  14. 1.8 8km ESE of Yorba Linda, CA
  15. 2.2 8km ESE of Yorba 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.4 on 2018-08-29 — it released about 12,000 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.