128 km N of Isabela, Puerto Rico

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 1,700 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 6.7 200,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 8,800× the energy of this one
3. Magna, Utah 2020 M 5.7 6,200× the energy of this one
4. This earthquake M 3.2 about 1,700 lb of TNT
5. Around the size people start to feel M 3.0 this one released 1.8× 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.

Where

Epicentre 19.6590, -67.1526. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.7 83 km N of Isabela, Puerto Rico 08:30 UTC
2. 3.3 95 km NNW of San Antonio, Puerto Rico 05:28 UTC
3. 2.6 96 km N of Isabela, Puerto Rico 04:56 UTC
4. 2.9 90 km NNW of San Antonio, Puerto Rico 03:59 UTC
5. 3.0 106 km N of San Antonio, Puerto Rico 02:34 UTC
6. 2.9 105 km N of San Antonio, Puerto Rico 02:18 UTC
7. 3.0 91 km N of San Antonio, Puerto Rico 01:24 UTC
8. 3.1 90 km N of San Antonio, Puerto Rico 01:16 UTC
9. 2.9 101 km NNW of San Antonio, Puerto Rico 00:38 UTC
10. 3.2 95 km N of San Antonio, Puerto Rico 23:55 UTC
11. 2.9 104 km N of Isabela, Puerto Rico 23:20 UTC
12. 2.5 88 km NNW of San Antonio, Puerto Rico 23:03 UTC
13. 3.6 95 km NNW of San Antonio, Puerto Rico 22:10 UTC
14. 2.7 88 km NNW of San Antonio, Puerto Rico 21:23 UTC
15. 3.0 94 km NNW of San Antonio, Puerto Rico 21:19 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:52 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 4.2 on 2017-08-27 — it released about 33 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.