131 km N of San Juan, 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 50 km (31 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 2.5 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 68,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 3,000× the energy of this one
3. Magna, Utah 2020 M 5.7 2,100× the energy of this one
4. This earthquake M 3.5 about 2.5 tons of TNT
5. Around the size people start to feel M 3.0 this one released 5.2× 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 4.4 on 2016-10-23 — about 24 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

1. 5.4 106 km N of Brenas, Puerto Rico · 34 km SW of this epicentre Nov 2, 2008
2. 5.0 113 km N of Brenas, Puerto Rico · 25 km SW of this epicentre Nov 23, 2008

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 19.6520, -66.1565. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.6 93 km N of Brenas, Puerto Rico 00:55 UTC
2. 3.3 110 km N of Suárez, Puerto Rico 22:15 UTC
3. 3.2 93 km N of San Juan, Puerto Rico 13:29 UTC
4. 3.7 117 km N of San Juan, Puerto Rico 07:54 UTC
5. 3.4 123 km N of Tierras Nuevas Poniente, Puerto Rico 02:52 UTC
6. 3.3 113 km NNE of San Juan, Puerto Rico 05:26 UTC
7. 3.4 121 km NNE of San Juan, Puerto Rico 23:24 UTC
8. 3.6 95 km N of San Juan, Puerto Rico 16:05 UTC
9. 3.4 108 km NNE of San Juan, Puerto Rico 04:06 UTC
10. 3.6 104 km N of San Juan, Puerto Rico 05:34 UTC
11. 3.8 113 km N of San Juan, Puerto Rico 03:59 UTC
12. 3.3 107 km N of San Juan, Puerto Rico 18:02 UTC
13. 3.6 124 km N of Brenas, Puerto Rico 13:08 UTC
14. 3.3 108 km N of San Juan, Puerto Rico 07:07 UTC
15. 3.1 110 km N of San Juan, Puerto Rico 00:31 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:27 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.