140 km NNE of Vieques, Puerto Rico

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 33 km (21 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 1,800 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 190,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 8,500× the energy of this one
3. Magna, Utah 2020 M 5.7 6,000× the energy of this one
4. This earthquake M 3.2 about 1,800 lb of TNT
5. Around the size people start to feel M 3.0 this one released 1.9× 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 4.9 on 2018-11-14 — about 380 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

1. 6.0 112 km N of Charlotte Amalie, U.S. Virgin Islands · 42 km SE of this epicentre Oct 17, 2001
2. 5.6 112 km N of Charlotte Amalie, U.S. Virgin Islands · 46 km ESE of this epicentre Oct 16, 2001
3. 5.1 107 km N of Charlotte Amalie, U.S. Virgin Islands · 43 km SE of this epicentre May 11, 1996
4. 5.1 122 km NNE of Vieques, Puerto Rico · 19 km SSW of this epicentre Sep 6, 2004
5. 5.0 122 km N of Charlotte Amalie, U.S. Virgin Islands · 38 km ESE of this epicentre Mar 19, 1984

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 19.5713, -65.2633. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.4 114 km N of Suárez, Puerto Rico 21:55 UTC
2. 3.4 140 km NNE of Vieques, Puerto Rico 11:37 UTC
3. 3.7 131 km NNE of Vieques, Puerto Rico 09:49 UTC
4. 3.3 133 km NNE of Vieques, Puerto Rico 16:26 UTC
5. 3.4 130 km NNE of Vieques, Puerto Rico 23:11 UTC
6. 3.8 141 km NNE of Vieques, Puerto Rico 08:20 UTC
7. 3.7 137 km NNE of Vieques, Puerto Rico 08:21 UTC
8. 3.8 121 km NNE of Vieques, Puerto Rico 05:39 UTC
9. 4.0 143 km NNE of Vieques, Puerto Rico 22:45 UTC
10. 3.7 133 km NNE of Vieques, Puerto Rico 05:00 UTC
11. 3.4 106 km NNE of Vieques, Puerto Rico 01:59 UTC
12. 3.3 99 km N of Culebra, Puerto Rico 05:59 UTC
13. 3.9 143 km NNE of Vieques, Puerto Rico 01:40 UTC
14. 3.7 147 km N of Charlotte Amalie, U.S. Virgin Islands 18:17 UTC
15. 3.8 113 km NNE of Vieques, Puerto Rico 11:28 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 17:00 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.