QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5mw

2km SSE of Palomar Observatory, CA

· 7.4 km deep · released about 2.5 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Diego County 36 kmRiverside County 90 kmOrange County 93 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 3.5 (mw)
Depth
7.4 km below the surface
Felt
909 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
Nearest
San Diego County, 36 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1528 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 909 people have reported feeling it to USGS.

How big was it?

This earthquake released about 2.5 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 68,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 3,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,100× the energy of this one
  4. This earthquake M 3.5 about 2.5 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 5.2× 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 33.3420, -116.8575. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Diego County, CA 36 km (22 mi) NNW of here earthquakes near San Diego County
Riverside County, CA 90 km (56 mi) WSW of here earthquakes near Riverside County
Orange County, CA 93 km (58 mi) ESE of here earthquakes near Orange 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. 1.6 8km NNE of Borrego Springs, CA
  2. 1.6 8km NNE of Borrego Springs, CA
  3. 3.3 7km NNE of Borrego Springs, CA
  4. 1.8 10km SSE of Idyllwild, CA
  5. 1.9 10km SW of Idyllwild, CA
  6. 2.0 14km ESE of Anza, CA
  7. 2.2 13km WNW of Anza, CA
  8. 1.8 10km SSW of Idyllwild, CA
  9. 1.9 6km NW of Anza, CA
  10. 1.5 8km NW of Anza, CA
  11. 1.9 12km N of Borrego Springs, CA
  12. 1.6 2km ESE of Lake Henshaw, CA
  13. 1.7 16km ESE of Anza, CA
  14. 2.1 6km SE of Valle Vista, CA
  15. 1.6 17km ESE 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 370 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.