103 km N 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 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 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 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 · 38 km NE of this epicentre Sep 6, 1919
2. 6.1 91 km N of Charlotte Amalie, U.S. Virgin Islands · 13 km SSW of this epicentre Oct 11, 2008
3. 6.0 112 km N of Charlotte Amalie, U.S. Virgin Islands · 19 km WNW of this epicentre Oct 17, 2001
4. 5.9 68 km N of Cruz Bay, U.S. Virgin Islands · 37 km SSE of this epicentre Jun 25, 1930
5. 5.9 65 km NNE of Cruz Bay, U.S. Virgin Islands · 47 km SSE of this epicentre Jun 26, 1985

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 19.2679, -64.7802. 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. 3.9 67 km NNE of Cruz Bay, U.S. Virgin Islands 07:53 UTC
2. 3.1 89 km N of Charlotte Amalie, U.S. Virgin Islands 13:05 UTC
3. 3.4 97 km NNE of Cruz Bay, U.S. Virgin Islands 08:01 UTC
4. 3.9 112 km N of Cruz Bay, U.S. Virgin Islands 04:05 UTC
5. 3.7 97 km N of Cruz Bay, U.S. Virgin Islands 05:37 UTC
6. 2.9 63 km N of Charlotte Amalie, U.S. Virgin Islands 22:20 UTC
7. 3.3 77 km NNW of Charlotte Amalie, U.S. Virgin Islands 13:47 UTC
8. 3.4 71 km NNW of Charlotte Amalie, U.S. Virgin Islands 12:45 UTC
9. 3.0 56 km N of Charlotte Amalie, U.S. Virgin Islands 22:19 UTC
10. 3.4 126 km N of Cruz Bay, U.S. Virgin Islands 09:59 UTC
11. 3.2 100 km NNE of Cruz Bay, U.S. Virgin Islands 13:19 UTC
12. 3.4 99 km NNE of Cruz Bay, U.S. Virgin Islands 22:29 UTC
13. 3.3 62 km N of Charlotte Amalie, U.S. Virgin Islands 10:46 UTC
14. 3.6 67 km N of Charlotte Amalie, U.S. Virgin Islands 10:26 UTC
15. 3.6 136 km NNE of Cruz Bay, U.S. Virgin Islands 07:04 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 22:10 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.