QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4md

101 km N of Charlotte Amalie, U.S. Virgin Islands

Yes. A magnitude 3.4 earthquake was recorded 101 km N of Charlotte Amalie, U.S. Virgin Islands, at 4:32 pm AST on 3 September 2018 (20:32 UTC), 91 km deep. 1 person has reported feeling it to USGS.

· 91 km deep · released about 1.6 tons of TNT

10 km30 km60 km120 km N Culebra Municipio 115 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 3.4 (md)
Depth
91 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Culebra Municipio, 115 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2924 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 it was probably too small to be felt, even directly above it. 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 1.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 110,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,700× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,300× the energy of this one
  4. This earthquake M 3.4 about 1.6 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 3.3× 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

The largest earthquake within 50 km since 2016 was M 4.5 on 2018-02-09 — about 53 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 131 km NNE of Cruz Bay, U.S. Virgin Islands · 43 km NE of this epicentre
  2. 6.1 91 km N of Charlotte Amalie, U.S. Virgin Islands · 10 km S of this epicentre
  3. 6.0 112 km N of Charlotte Amalie, U.S. Virgin Islands · 16 km NW of this epicentre
  4. 5.9 68 km N of Cruz Bay, U.S. Virgin Islands · 37 km SSE of this epicentre
  5. 5.9 65 km NNE of Cruz Bay, U.S. Virgin Islands · 48 km SSE 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 19.2541, -64.8276. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Culebra Municipio, PR 115 km (71 mi) SSW earthquakes near Culebra Municipio
Fajardo Municipio, PR 125 km (78 mi) SW earthquakes near Fajardo Municipio
Luquillo Municipio, PR 135 km (84 mi) SW earthquakes near Luquillo Municipio
Ceiba Municipio, PR 139 km (86 mi) SW earthquakes near Ceiba Municipio
Río Grande Municipio, PR 141 km (88 mi) SW earthquakes near Río Grande Municipio
Loíza Municipio, PR 148 km (92 mi) SW earthquakes near Loíza Municipio

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

Aftershocks so far

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

  1. 3.4 92 km N of Cruz Bay, U.S. Virgin Islands
  2. 3.2 103 km N of Cruz Bay, U.S. Virgin Islands
  3. 3.6 119 km NNW of Charlotte Amalie, U.S. Virgin Islands
  4. 3.0 60 km NNW of Charlotte Amalie, U.S. Virgin Islands
  5. 2.6 81 km N of Culebra, Puerto Rico
  6. 3.3 67 km NNW of Charlotte Amalie, U.S. Virgin Islands
  7. 2.5 65 km N of Charlotte Amalie, U.S. Virgin Islands
  8. 3.5 71 km N of Charlotte Amalie, U.S. Virgin Islands
  9. 2.8 93 km N of Culebra, Puerto Rico
  10. 3.1 68 km NNE of Cruz Bay, U.S. Virgin Islands
  11. 3.2 85 km NNE of Cruz Bay, U.S. Virgin Islands
  12. 3.4 78 km N of Charlotte Amalie, U.S. Virgin Islands
  13. 3.1 108 km N of Culebra, Puerto Rico
  14. 2.3 68 km N of Cruz Bay, U.S. Virgin Islands
  15. 2.7 104 km N 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.