QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5Md

Earthquake near Bairoa, PR

No earthquake was likely felt in Bairoa in the 24 hours to 9:42 am AST (13:42 UTC). The last one was M 4.1, 82 km (51 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 Bairoa

This page: a magnitude 2.5 earthquake was recorded in Bairoa, PR, at 1:01 am AST on 20 December 2016 (05:01 UTC), 24 km deep.

USGS: 1 km WSW of Bairoa, Puerto Rico

in Caguas, PR

1:01 am AST, Dec 20, 2016 · · 24 km deep · released about 170 lb of TNT

Every earthquake near Bairoa Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Caguas Municipio 5 kmGurabo Municipio 8 kmAguas Buenas Municipio 8 kmTrujillo Alto Municipio 10 kmGuaynabo Municipio 12 kmSan Lorenzo Municipio 14 kmCidra Municipio 15 kmJuncos Municipio 16 kmBayamón Municipio 16 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
1:01 am AST on 20 December 2016 ()
Where
in Bairoa, PR · earthquakes near Bairoa
Magnitude
M 2.5 (Md)
Depth
24 km below the surface
Felt
no reports yet
Nearest
Caguas Municipio, 5 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3613 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. 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: Caguas, Aguas Buenas, Gurabo, Sumidero, Celada, Santa Clara.

How big was it?

This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 lb of TNT

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 4.6 on 2016-12-05 — about 1,400 times the energy of this one.

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 · 9 km W of this epicentre
  2. 5.0 3 km N of Brenas, Puerto Rico · 41 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 18.2551, -66.0530. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Caguas Municipio, PR 5 km (3 mi) S earthquakes near Caguas Municipio
Gurabo Municipio, PR 8 km (5 mi) ENE earthquakes near Gurabo Municipio
Aguas Buenas Municipio, PR 8 km (5 mi) W earthquakes near Aguas Buenas Municipio
Trujillo Alto Municipio, PR 10 km (6 mi) NNE earthquakes near Trujillo Alto Municipio
Guaynabo Municipio, PR 12 km (7 mi) NNW earthquakes near Guaynabo Municipio
San Lorenzo Municipio, PR 14 km (9 mi) SE earthquakes near San Lorenzo Municipio

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. 1.6 3 km SE of Punta Santiago, Puerto Rico
  2. 1.8 8 km SSW of Emajagua, Puerto Rico
  3. 2.2 10 km S of Emajagua, Puerto Rico
  4. 2.5 9 km S of Emajagua, Puerto Rico
  5. 2.5 20 km NNE of San Juan, Puerto Rico
  6. 2.4 11 km S of Emajagua, Puerto Rico
  7. 2.5 11 km S of Emajagua, Puerto Rico
  8. 2.7 11 km SE of Emajagua, Puerto Rico
  9. 2.1 11 km S of Emajagua, Puerto Rico
  10. 3.6 20 km NNW of Loíza, Puerto Rico
  11. 3.0 7 km S of Emajagua, Puerto Rico
  12. 3.0 10 km S of Emajagua, Puerto Rico
  13. 2.3 9 km S of Emajagua, Puerto Rico
  14. 1.5 2 km WSW of Las Piedras, Puerto Rico
  15. 3.1 1 km SSE of Pájaros, 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.