QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

4km W of Seal Beach, CA

· 12 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 36 kmLos Angeles County 51 kmVentura County 113 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
12 km below the surface
Felt
7 reports · strongest reported intensity III
Nearest
Orange County, 36 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1500 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 7 people have reported feeling it to USGS.

How big was it?

This earthquake released about 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 730,000× the energy of this one
  3. Around the size people start to feel M 3.0 65× the energy of this one
  4. This earthquake M 1.8 about 15 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 33.7490, -118.1520. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 36 km (22 mi) WNW of here earthquakes near Orange County
Los Angeles County, CA 51 km (32 mi) SSE of here earthquakes near Los Angeles County
Ventura County, CA 113 km (70 mi) SE of here earthquakes near Ventura County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 2.0 4km SW of Newport Beach, CA
  2. 1.8 3km SSW of Newport Beach, CA
  3. 1.8 3km SW of Newport Beach, CA
  4. 1.6 1km SSE of Carson, CA
  5. 1.8 5km WSW of Huntington Beach, CA
  6. 1.5 2km NNW of Rolling Hills Estates, CA
  7. 2.1 2km NNW of Rolling Hills Estates, CA
  8. 1.8 7km N of Yorba Linda, CA
  9. 1.6 3km SW of Yorba Linda, CA
  10. 1.6 2km ENE of La Habra, CA
  11. 1.7 4km NW of Diamond Bar, CA
  12. 2.1 18km S of San Pedro, CA
  13. 1.8 22km SSW of Newport Beach, CA
  14. 1.9 10km WSW of Corona, CA
  15. 1.5 4km NNW of Diamond Bar, 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 13,000 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.