QuakeIndex

Earthquake · reviewed by a seismologist

M 4.4mw

40 km S of San Clemente Is. (SE tip), CA

· 5.9 km deep · released about 67 tons of TNT

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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 4.4 (mw)
Depth
5.9 km below the surface
Felt
366 reports · strongest reported intensity IV
Measured shaking
intensity III (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 271 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 366 people have reported feeling it to USGS.

How big was it?

This earthquake released about 67 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 2,500× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 110× the energy of this one
  3. Magna, Utah 2020 M 5.7 80× the energy of this one
  4. This earthquake M 4.4 about 67 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 140× 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 32.4637, -118.2878. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.5 12 km SSE of San Clemente Is. (SE tip), CA
  2. 2.1 69 km SE of San Clemente Is. (SE tip), CA
  3. 2.9 10 km WNW of San Clemente Is. (SE tip), CA
  4. 2.0 63 km WSW of Coronado, CA
  5. 3.2 72 km SE of San Clemente Is. (SE tip), CA
  6. 2.6 68 km SE of San Clemente Is. (SE tip), CA
  7. 2.6 25 km ESE of San Clemente Is. (SE tip), CA
  8. 1.8 37 km SE of San Clemente Is. (SE tip), CA
  9. 2.3 55 km SE of San Clemente Is. (SE tip), CA
  10. 2.6 6 km SE of San Clemente Is. (SE tip), CA
  11. 3.0 25 km SE of San Clemente Is. (SE tip), CA
  12. 2.3 6 km SSE of San Clemente Is. (SE tip), CA
  13. 3.0 8 km SSE of San Clemente Is. (SE tip), CA
  14. 2.9 39 km WSW of San Clemente Is. (SE tip), CA
  15. 2.5 31 km ESE of San Clemente Is. (SE tip), 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 4.3 on 2019-06-05.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.