QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1md

36 km NW of Saint Croix, U.S. Virgin Islands

Yes. A magnitude 3.1 earthquake was recorded 36 km NW of Saint Croix, U.S. Virgin Islands, at 3:04 am AST on 7 May 2018 (07:04 UTC), 7.0 km deep.

· 7.0 km deep · released about 1,200 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Vieques Municipio 50 kmCulebra Municipio 52 kmCeiba Municipio 74 kmFajardo Municipio 78 kmNaguabo Municipio 83 kmHumacao Municipio 86 kmLuquillo Municipio 88 kmYabucoa Municipio 92 kmMaunabo Municipio 95 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 3.1 (md)
Depth
7.0 km below the surface
Felt
no reports yet
Nearest
Vieques Municipio, 50 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3017 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 40 km (25 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 1,200 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 280,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 12,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 8,800× the energy of this one
  4. This earthquake M 3.1 about 1,200 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.3× 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 6.1 22 km NNE of Saint Croix, U.S. Virgin Islands · 39 km E of this epicentre
  2. 5.0 29 km S of Cruz Bay, U.S. Virgin Islands · 29 km ENE of this epicentre

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 17.9595, -64.9975. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Vieques Municipio, PR 50 km (31 mi) WNW earthquakes near Vieques Municipio
Culebra Municipio, PR 52 km (33 mi) NW earthquakes near Culebra Municipio
Ceiba Municipio, PR 74 km (46 mi) WNW earthquakes near Ceiba Municipio
Fajardo Municipio, PR 78 km (49 mi) NW earthquakes near Fajardo Municipio
Naguabo Municipio, PR 83 km (52 mi) WNW earthquakes near Naguabo Municipio
Humacao Municipio, PR 86 km (53 mi) WNW earthquakes near Humacao Municipio

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

Aftershocks so far

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

  1. 2.9 10 km SSE of Esperanza, Puerto Rico
  2. 2.2 33 km S of Charlotte Amalie, U.S. Virgin Islands
  3. 2.2 Virgin Islands
  4. 2.2 18 km SSW of Charlotte Amalie, U.S. Virgin Islands
  5. 2.3 18 km WNW of Saint Croix, U.S. Virgin Islands
  6. 2.6 29 km ESE of Esperanza, Puerto Rico
  7. 2.4 30 km SSE of Esperanza, Puerto Rico
  8. 3.1 8 km W of Charlotte Amalie, U.S. Virgin Islands
  9. 3.0 36 km SE of Esperanza, Puerto Rico
  10. 2.3 21 km SE of Isabel Segunda, Puerto Rico
  11. 3.1 12 km E of Culebra, Puerto Rico
  12. 3.0 10 km WNW of Charlotte Amalie, U.S. Virgin Islands
  13. 1.8 23 km SSE of Esperanza, Puerto Rico
  14. 2.9 31 km SSW of Charlotte Amalie, U.S. Virgin Islands
  15. 2.6 17 km SE of Esperanza, Puerto Rico

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.