QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

4km SSW of San Dimas, CA

· 4.7 km deep · released about 19 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Los Angeles County 43 kmOrange County 45 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 1.9 (ml)
Depth
4.7 km below the surface
Felt
3 reports · strongest reported intensity II
Nearest
Los Angeles County, 43 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1511 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 19 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 790,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 560,000× the energy of this one
  3. Around the size people start to feel M 3.0 50× the energy of this one
  4. This earthquake M 1.9 about 19 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 34.0767, -117.8198. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Los Angeles County, CA 43 km (27 mi) ESE of here earthquakes near Los Angeles County
Orange County, CA 45 km (28 mi) N of here earthquakes near Orange County
San Diego County, CA 152 km (94 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

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

  1. 1.7 5km WSW of Lytle Creek, CA
  2. 1.7 2km W of Willowbrook, CA
  3. 3.5 2km W of Willowbrook, CA
  4. 1.5 10km SW of Corona, CA
  5. 2.1 5km W of Devore, CA
  6. 2.0 8km E of Yorba Linda, CA
  7. 2.2 4km ESE of Altadena, CA
  8. 1.9 4km NNW of Orange, CA
  9. 1.5 2km SW of La Habra, CA
  10. 1.6 2km SW of La Habra, CA
  11. 1.7 2km SE of Placentia, CA
  12. 2.7 2km SSE of Placentia, CA
  13. 1.6 3km W of South El Monte, CA
  14. 1.8 2km NNE of Villa Park, CA
  15. 1.6 7km SSE 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 10,000 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.