QuakeIndex

Earthquake · reviewed by a seismologist

M 4.0md

Virgin Islands

Yes. A magnitude 4.0 earthquake was recorded in the Virgin Islands at 06:56 UTC on 2023-07-20, 38 km deep.

· 38 km deep · released about 18 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 4.0 (md)
Depth
38 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1140 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 93 km (58 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 18 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 9,400× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 420× the energy of this one
  3. Magna, Utah 2020 M 5.7 300× the energy of this one
  4. This earthquake M 4.0 about 18 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 38× 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 in our catalogue was M 5.0 on 2019-10-06 — about 23 times the energy of this one.

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 19.6020, -64.4203. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.9 163 km NNE of Cruz Bay, U.S. Virgin Islands
  2. 3.7 115 km N of Charlotte Amalie, U.S. Virgin Islands
  3. 3.7 168 km NNE of Cruz Bay, U.S. Virgin Islands
  4. 3.6 153 km NNE of Cruz Bay, U.S. Virgin Islands
  5. 3.9 149 km N of Cruz Bay, U.S. Virgin Islands
  6. 4.0 144 km N of Cruz Bay, U.S. Virgin Islands
  7. 3.8 150 km N of Cruz Bay, U.S. Virgin Islands
  8. 3.9 141 km N of Cruz Bay, U.S. Virgin Islands
  9. 4.0 159 km N of Cruz Bay, U.S. Virgin Islands
  10. 3.7 146 km NNE of Cruz Bay, U.S. Virgin Islands
  11. 3.6 104 km NNE of Cruz Bay, U.S. Virgin Islands
  12. 3.8 176 km NNE of Cruz Bay, U.S. Virgin Islands
  13. 3.9 161 km NNE of Cruz Bay, U.S. Virgin Islands
  14. 3.8 146 km N of Cruz Bay, U.S. Virgin Islands
  15. 2.9 141 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.