QuakeIndex

Earthquake · reviewed by a seismologist

M 4.0mw

5km WSW of Palomar Observatory, CA

· 13 km deep · released about 15 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Diego County 37 kmOrange County 88 kmRiverside County 95 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 4.0 (mw)
Depth
13 km below the surface
Felt
5794 reports · strongest reported intensity V
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
San Diego County, 37 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1307 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 5794 people have reported feeling it to USGS.

How big was it?

This earthquake released about 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 11,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 500× the energy of this one
  3. Magna, Utah 2020 M 5.7 350× the energy of this one
  4. This earthquake M 4.0 about 15 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 32× 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 33.3355, -116.9147. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Diego County, CA 37 km (23 mi) NNW of here earthquakes near San Diego County
Orange County, CA 88 km (55 mi) ESE of here earthquakes near Orange County
Riverside County, CA 95 km (59 mi) WSW of here earthquakes near Riverside County

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

Aftershocks so far

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

  1. 1.8 3km NNW of Palomar Observatory, CA
  2. 2.0 10km S of Idyllwild, CA
  3. 1.9 16km ESE of Anza, CA
  4. 1.8 14km N of Warner Springs, CA
  5. 1.7 4km WNW of Camp Pendleton South, CA
  6. 2.4 14km NE of Julian, CA
  7. 1.6 14km N of Warner Springs, CA
  8. 2.0 3km NNW of Palomar Observatory, CA
  9. 1.9 13km WNW of Anza, CA
  10. 1.6 17km ESE of Anza, CA
  11. 1.5 22km ESE of Anza, CA
  12. 1.7 6km NNW of Lakeside, CA
  13. 1.7 13km ESE of Anza, CA
  14. 1.8 13km WNW of Anza, CA
  15. 2.4 13km SE of Anza, 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 5.2 on 2016-06-10 — it released about 61 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.