QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9Md

Earthquake near Aguas Buenas, PR

No earthquake was likely felt in Aguas Buenas in the 24 hours to 4:39 pm AST (20:39 UTC). The last one was M 4.1, 87 km (54 mi) ESE, at 5:44 am AST on 28 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near Aguas Buenas

This page: a magnitude 3.9 earthquake was recorded 7 km (4 mi) west-northwest of Aguas Buenas, PR, at 9:24 pm AST on 13 October 2016 (01:24 UTC), 131 km deep. 15 people have reported feeling it to USGS.

USGS: 6 km WNW of Aguas Buenas, Puerto Rico

18 km (11 mi) SW of San Juan, PR · 12 km (7 mi) S of Bayamón, PR

9:24 pm AST, Oct 13, 2016 · · 131 km deep · released about 11 tons of TNT

Every earthquake near Aguas Buenas Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aguas Buenas Municipio 4 kmComerío Municipio 8 kmBayamón Municipio 8 kmGuaynabo Municipio 9 kmNaranjito Municipio 9 kmCidra Municipio 11 kmToa Alta Municipio 13 kmCaguas Municipio 14 kmCorozal Municipio 17 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
9:24 pm AST on 13 October 2016 ()
Where
7 km (4 mi) west-northwest of Aguas Buenas, PR · earthquakes near Aguas Buenas
Magnitude
M 3.9 (Md)
Depth
131 km below the surface
Felt
15 reports · strongest reported intensity III
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Aguas Buenas Municipio, 4 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3588 days ago

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. In Aguas Buenas, 7 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.

Earthquakes near other towns within 30 km: Sumidero, Santa Clara, Naranjito, Comerío, Guaynabo, Cidra.

How big was it?

This earthquake released about 11 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 16,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 710× the energy of this one
  3. Magna, Utah 2020 M 5.7 500× the energy of this one
  4. This earthquake M 3.9 about 11 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 22× 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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

  1. 5.1 3 km W of Aguas Buenas, Puerto Rico · 4 km ESE of this epicentre
  2. 5.0 3 km N of Brenas, Puerto Rico · 31 km NW of this epicentre

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 18.2752, -66.1652. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguas Buenas Municipio, PR 4 km (3 mi) ESE earthquakes near Aguas Buenas Municipio
Comerío Municipio, PR 8 km (5 mi) SW earthquakes near Comerío Municipio
Bayamón Municipio, PR 8 km (5 mi) N earthquakes near Bayamón Municipio
Guaynabo Municipio, PR 9 km (6 mi) NE earthquakes near Guaynabo Municipio
Naranjito Municipio, PR 9 km (6 mi) W earthquakes near Naranjito Municipio
Cidra Municipio, PR 11 km (7 mi) S earthquakes near Cidra Municipio

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

Aftershocks so far

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

  1. 2.1 1 km WSW of Río Blanco, Puerto Rico
  2. 1.9 1 km NE of Río Blanco, Puerto Rico
  3. 2.3 1 km N of Antón Ruiz, Puerto Rico
  4. 1.9 5 km N of Suárez, Puerto Rico
  5. 1.8 2 km ENE of Vieques, Puerto Rico
  6. 1.8 2 km N of Vieques, Puerto Rico
  7. 1.7 1 km E of Bajandas, Puerto Rico
  8. 2.2 2 km E of Potala Pastillo, Puerto Rico
  9. 2.2 1 km SW of Salinas, Puerto Rico
  10. 2.4 4 km ESE of Villalba, Puerto Rico
  11. 2.7 1 km WNW of Potala Pastillo, Puerto Rico
  12. 2.4 3 km NNW of Jagual, Puerto Rico
  13. 2.5 7 km NNW of Trujillo Alto, Puerto Rico
  14. 3.0 5 km SE of Pájaros, Puerto Rico
  15. 2.6 4 km S of G. L. Garcia, Puerto Rico

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

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.