124 km NNE of Cruz Bay, U.S. Virgin Islands

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 30 km (19 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 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
3. Around the size people start to feel M 3.0 1.4× the energy of this one
4. This earthquake M 2.9 about 680 lb of TNT

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 5.0 on 2021-02-06 — about 1,400 times the energy of this one.

Before 2016, the USGS record lists 14 earthquakes of M5 or more within 50 km; the five largest:

1. 6.2 131 km NNE of Cruz Bay, U.S. Virgin Islands · 9 km NE of this epicentre Sep 6, 1919
2. 6.1 91 km N of Charlotte Amalie, U.S. Virgin Islands · 42 km SW of this epicentre Oct 11, 2008
3. 6.0 112 km N of Charlotte Amalie, U.S. Virgin Islands · 40 km WSW of this epicentre Oct 17, 2001
4. 5.7 80 km NNE of Cruz Bay, U.S. Virgin Islands · 46 km S of this epicentre Aug 2, 1927
5. 5.6 112 km N of Charlotte Amalie, U.S. Virgin Islands · 35 km WSW of this epicentre Oct 16, 2001

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 19.4360, -64.5599. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 3.4 120 km N of Cruz Bay, U.S. Virgin Islands 19:13 UTC
2. 3.4 89 km NNE of Cruz Bay, U.S. Virgin Islands 08:11 UTC
3. 3.5 99 km NNE of Cruz Bay, U.S. Virgin Islands 05:25 UTC
4. 3.4 102 km N of Charlotte Amalie, U.S. Virgin Islands 02:47 UTC
5. 3.2 89 km N of Cruz Bay, U.S. Virgin Islands 22:40 UTC
6. 3.3 96 km N of Cruz Bay, U.S. Virgin Islands 11:44 UTC
7. 3.4 116 km N of Charlotte Amalie, U.S. Virgin Islands 09:06 UTC
8. 3.7 130 km N of Charlotte Amalie, U.S. Virgin Islands 01:53 UTC
9. 3.4 109 km N of Charlotte Amalie, U.S. Virgin Islands 13:31 UTC
10. 3.4 104 km N of Charlotte Amalie, U.S. Virgin Islands 02:41 UTC
11. 3.7 119 km N of Charlotte Amalie, U.S. Virgin Islands 02:36 UTC
12. 3.4 82 km N of Charlotte Amalie, U.S. Virgin Islands 16:33 UTC
13. 3.5 136 km NNE of Cruz Bay, U.S. Virgin Islands 10:16 UTC
14. 3.5 106 km N of Charlotte Amalie, U.S. Virgin Islands 08:08 UTC
15. 3.7 132 km N of Charlotte Amalie, U.S. Virgin Islands 06:35 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 18:48 UTC. 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.