QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9md

117 km N of Cruz Bay, U.S. Virgin Islands

· 28 km deep · released about 12 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 3.9 (md)
Depth
28 km below the surface
Felt
no reports yet
Nearest
Culebra Municipio, 134 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1408 days ago

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

How big was it?

This earthquake released about 12 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 14,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 640× the energy of this one
  3. Magna, Utah 2020 M 5.7 450× the energy of this one
  4. This earthquake M 3.9 about 12 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 25× 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 19.3853, -64.6968. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Culebra Municipio, PR 134 km (83 mi) NNE of here earthquakes near Culebra Municipio
Fajardo Municipio, PR 145 km (90 mi) NE of here earthquakes near Fajardo Municipio
Luquillo Municipio, PR 155 km (97 mi) NE of here earthquakes near Luquillo Municipio
Río Grande Municipio, PR 161 km (100 mi) NE of here earthquakes near Río Grande Municipio

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

Aftershocks so far

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

  1. 3.8 121 km NNE of Cruz Bay, U.S. Virgin Islands
  2. 3.4 76 km N of Cruz Bay, U.S. Virgin Islands
  3. 3.6 115 km N of Charlotte Amalie, U.S. Virgin Islands
  4. 3.7 75 km N of Charlotte Amalie, U.S. Virgin Islands
  5. 3.9 79 km N of Charlotte Amalie, U.S. Virgin Islands
  6. 3.6 Virgin Islands
  7. 3.7 Virgin Islands
  8. 3.6 114 km NNW of Charlotte Amalie, U.S. Virgin Islands
  9. 3.8 140 km N of Charlotte Amalie, U.S. Virgin Islands
  10. 3.0 81 km N of Charlotte Amalie, U.S. Virgin Islands
  11. 3.5 85 km N of Charlotte Amalie, U.S. Virgin Islands
  12. 3.5 Virgin Islands
  13. 3.7 95 km N of Cruz Bay, U.S. Virgin Islands
  14. 3.9 67 km N of Cruz Bay, U.S. Virgin Islands
  15. 3.3 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.

For this area

The largest earthquake within 50 km in our catalogue was M 5.0 on 2021-02-06 — it released about 39 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.