QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4md

73 km ENE of Cruz Bay, U.S. Virgin Islands

Yes. A magnitude 3.4 earthquake was recorded 73 km ENE of Cruz Bay, U.S. Virgin Islands, at 8:11 am AST on 21 August 2022 (12:11 UTC), 52 km deep.

· 52 km deep · released about 1.9 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 3.4 (md)
Depth
52 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1471 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 25 km (16 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 1.9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 89,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,800× the energy of this one
  4. This earthquake M 3.4 about 1.9 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 4× 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.

For this area

The largest earthquake within 50 km since 2016 was M 5.5 on 2022-05-08 — about 1,400 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 18.6202, -64.1658. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.1 70 km NNE of Cruz Bay, U.S. Virgin Islands
  2. 3.4 78 km NE of Cruz Bay, U.S. Virgin Islands
  3. 2.8 60 km NE of Cruz Bay, U.S. Virgin Islands
  4. 3.8 71 km E of Cruz Bay, U.S. Virgin Islands
  5. 3.3 53 km NNE of Cruz Bay, U.S. Virgin Islands
  6. 3.5 76 km NE of Cruz Bay, U.S. Virgin Islands
  7. 3.0 46 km NE of Cruz Bay, U.S. Virgin Islands
  8. 3.3 Virgin Islands
  9. 3.8 Virgin Islands
  10. 3.8 75 km NE of Cruz Bay, U.S. Virgin Islands
  11. 3.2 Virgin Islands
  12. 3.6 Virgin Islands
  13. 3.5 24 km ENE of Cruz Bay, U.S. Virgin Islands
  14. 4.6 70 km NE of Cruz Bay, U.S. Virgin Islands
  15. 3.4 48 km NNE of Cruz Bay, U.S. Virgin Islands

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.

On USGS

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