Earthquake · reviewed by a seismologist
M 4.7mwr
43 km NNE of Cruz Bay, U.S. Virgin Islands
Yes. A magnitude 4.7 earthquake was recorded 43 km NNE of Cruz Bay, U.S. Virgin Islands, at 5:21 pm AST on 6 April 2018 (21:21 UTC), 40 km deep. 154 people have reported feeling it to USGS.
- When
- Magnitude
- M 4.7 (mwr)
- Depth
- 40 km below the surface
- Felt
- 154 reports · strongest reported intensity IV
- Nearest
- Culebra Municipio, 79 km WSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1653 days ago
Earthquake alerts for Culebra, PR
Get a notification in this browser when USGS records an earthquake near Culebra, PR. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 154 km (96 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 170 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.7 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 1,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 45× the energy of this one
- Magna, Utah 2020 M 5.7 32× the energy of this one
- This earthquake M 4.7 about 170 tons of TNT
- Around the size people start to feel M 3.0 this one released 350× 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 (31 mi) since our catalogue begins in 2016. The previous largest was M 4.5 on 2018-02-09.
Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:
- 5.9 68 km N of Cruz Bay, U.S. Virgin Islands · 27 km N of this epicentre
- 5.9 65 km NNE of Cruz Bay, U.S. Virgin Islands · 23 km NNE of this epicentre
- 5.7 80 km NNE of Cruz Bay, U.S. Virgin Islands · 37 km NNE of this epicentre
- 5.3 78 km NNE of Cruz Bay, U.S. Virgin Islands · 36 km N of this epicentre
- 5.2 36 km NNE of Cruz Bay, U.S. Virgin Islands · 7 km SSW 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 18.7020, -64.6711. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Culebra Municipio, PR | 79 km (49 mi) | WSW | earthquakes near Culebra Municipio |
| Vieques Municipio, PR | 103 km (64 mi) | SW | earthquakes near Vieques Municipio |
| Fajardo Municipio, PR | 103 km (64 mi) | WSW | earthquakes near Fajardo Municipio |
| Ceiba Municipio, PR | 112 km (70 mi) | WSW | earthquakes near Ceiba Municipio |
| Luquillo Municipio, PR | 116 km (72 mi) | WSW | earthquakes near Luquillo Municipio |
| Río Grande Municipio, PR | 124 km (77 mi) | WSW | earthquakes near Río Grande Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
50 earthquakes have been recorded within 50 km since this one.
- 3.6 80 km NE of Cruz Bay, U.S. Virgin Islands
- 3.4 75 km NNE of Cruz Bay, U.S. Virgin Islands
- 3.4 41 km NNE of Cruz Bay, U.S. Virgin Islands
- 2.8 45 km N of Charlotte Amalie, U.S. Virgin Islands
- 3.2 76 km NE of Cruz Bay, U.S. Virgin Islands
- 3.1 63 km NE of Cruz Bay, U.S. Virgin Islands
- 3.1 77 km NE of Cruz Bay, U.S. Virgin Islands
- 3.1 32 km N of Charlotte Amalie, U.S. Virgin Islands
- 3.1 57 km N of Cruz Bay, U.S. Virgin Islands
- 3.3 86 km N of Cruz Bay, U.S. Virgin Islands
- 3.5 72 km NE of Cruz Bay, U.S. Virgin Islands
- 3.1 21 km NNE of Charlotte Amalie, U.S. Virgin Islands
- 3.4 74 km N of Charlotte Amalie, U.S. Virgin Islands
- 3.2 36 km NNE of Cruz Bay, U.S. Virgin Islands
- 3.3 71 km N of Charlotte Amalie, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.