QuakeIndex

Earthquake · reviewed by a seismologist

M 4.1mw

3km ENE of Westmorland, CA

· 11 km deep · released about 23 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Imperial County 22 kmRiverside County 85 kmSan Diego County 110 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 4.1 (mw)
Depth
11 km below the surface
Felt
12 reports · strongest reported intensity III
Measured shaking
intensity V (ShakeMap)
USGS impact alert
green
Nearest
Imperial County, 22 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1858 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 12 people have reported feeling it to USGS.

How big was it?

This earthquake released about 23 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 7,400× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 330× the energy of this one
  3. Magna, Utah 2020 M 5.7 230× the energy of this one
  4. This earthquake M 4.1 about 23 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 48× more

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 33.0443, -115.5928. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Imperial County, CA 22 km (14 mi) W of here earthquakes near Imperial County
Riverside County, CA 85 km (53 mi) SSE of here earthquakes near Riverside County
San Diego County, CA 110 km (69 mi) E 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

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

  1. 2.3 4km E of Westmorland, CA
  2. 2.4 4km NE of Westmorland, CA
  3. 2.6 4km NNE of Westmorland, CA
  4. 2.1 3km NE of Westmorland, CA
  5. 1.5 4km NNE of Westmorland, CA
  6. 1.7 2km E of Westmorland, CA
  7. 1.8 4km NE of Westmorland, CA
  8. 1.7 3km ENE of Westmorland, CA
  9. 1.5 3km ESE of Westmorland, CA
  10. 1.7 4km ENE of Westmorland, CA
  11. 2.0 4km NE of Westmorland, CA
  12. 2.4 3 km NE of Westmorland, California
  13. 1.8 3km E of Westmorland, CA
  14. 1.7 3km E of Westmorland, CA
  15. 1.9 3km ENE of Westmorland, 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 4.9 on 2020-10-01 — it released about 16 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.