Earthquake near San Juan, PR

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 47 km (29 mi) from the epicentre. In San Juan, 47 km away, the estimate is intensity II (weak). 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.

Likely felt in: Coamo 9 km, intensity III · Río Cañas Abajo 14 km, intensity III · Santa Isabel 21 km, intensity II · Jayuya 22 km, intensity II · Ciales 22 km, intensity II · Corozal 23 km, intensity II · Cayey 25 km, intensity II · Ponce 28 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1 tons 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 6.7 170,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 7,400× the energy of this one
3. Magna, Utah 2020 M 5.7 5,200× the energy of this one
4. This earthquake M 3.2 about 1 tons of TNT
5. Around the size people start to feel M 3.0 this one released 2.1× 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 6.4 on 2020-01-07 — about 59,000 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

1. 5.8 12 km N of Garrochales, Puerto Rico · 49 km NNW of this epicentre Oct 12, 1918
2. 5.1 3 km W of Aguas Buenas, Puerto Rico · 31 km ENE of this epicentre Dec 24, 2010
3. 5.0 3 km N of Brenas, Puerto Rico · 39 km N of this epicentre Jun 17, 1975

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 18.1513, -66.4003. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 2.2 2 km NNW of Indios, Puerto Rico 05:51 UTC
2. 1.9 3 km SE of Salinas, Puerto Rico 04:22 UTC
3. 2.0 6 km SSE of Salinas, Puerto Rico 00:01 UTC
4. 2.8 2 km WNW of Guayanilla, Puerto Rico 13:43 UTC
5. 3.3 2 km W of Guayanilla, Puerto Rico 13:16 UTC
6. 2.6 4 km SW of Adjuntas, Puerto Rico 14:14 UTC
7. 2.0 10 km SW of Central Aguirre, Puerto Rico 09:42 UTC
8. 2.7 6 km S of Salinas, Puerto Rico 08:38 UTC
9. 1.8 0 km WSW of Salinas, Puerto Rico 08:22 UTC
10. 2.2 6 km S of Salinas, Puerto Rico 06:39 UTC
11. 2.4 7 km S of Salinas, Puerto Rico 18:06 UTC
12. 3.2 6 km S of Salinas, Puerto Rico 17:23 UTC
13. 2.8 1 km NE of Magas Arriba, Puerto Rico 15:17 UTC
14. 2.4 5 km S of Salinas, Puerto Rico 13:35 UTC
15. 2.2 8 km S of Salinas, Puerto Rico 09:18 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:22 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.