QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near Brenas, PR

No earthquake was likely felt in Brenas in the 24 hours to 10:44 am AST (14:44 UTC). The last one was M 4.8, 87 km (54 mi) SW, at 9:19 am AST on 18 September 2026, estimated intensity III (weak) in town; 86 felt reports to USGS. Every earthquake near Brenas

This page: a magnitude 2.8 earthquake was recorded 5 km (3 mi) north-northwest of Brenas, PR, at 4:36 am AST on 31 August 2023 (08:36 UTC), 80 km deep.

USGS: 5 km NNW of Brenas, Puerto Rico

33 km (21 mi) WNW of San Juan, PR · 25 km (16 mi) NW of Bayamón, PR

4:36 am AST, Aug 31, 2023 · · 80 km deep · released about 460 lb of TNT

Every earthquake near Brenas Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Vega Baja Municipio 8 kmVega Alta Municipio 9 kmDorado Municipio 11 kmManatí Municipio 16 kmToa Baja Municipio 18 kmToa Alta Municipio 20 kmBarceloneta Municipio 22 kmMorovis Municipio 23 kmCataño Municipio 23 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
4:36 am AST on 31 August 2023 ()
Where
5 km (3 mi) north-northwest of Brenas, PR · earthquakes near Brenas
Magnitude
M 2.8 (md)
Depth
80 km below the surface
Felt
no reports yet
Nearest
Vega Baja Municipio, 8 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1168 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 Brenas, 5 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: Sabana, Ceiba, Vega Baja, Monserrate, San Antonio, Dorado.

How big was it?

This earthquake released about 460 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 33,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 23,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.1× the energy of this one
  4. This earthquake M 2.8 about 460 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 4.8 on 2017-08-18 — about 1,000 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 · 23 km WNW of this epicentre
  2. 5.1 3 km W of Aguas Buenas, Puerto Rico · 36 km SE of this epicentre
  3. 5.0 3 km N of Brenas, Puerto Rico · 2 km SE 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 18.5112, -66.3560. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Vega Baja Municipio, PR 8 km (5 mi) SW earthquakes near Vega Baja Municipio
Vega Alta Municipio, PR 9 km (5 mi) SSE earthquakes near Vega Alta Municipio
Dorado Municipio, PR 11 km (7 mi) ESE earthquakes near Dorado Municipio
Manatí Municipio, PR 16 km (10 mi) WSW earthquakes near Manatí Municipio
Toa Baja Municipio, PR 18 km (11 mi) ESE earthquakes near Toa Baja Municipio
Toa Alta Municipio, PR 20 km (12 mi) SE earthquakes near Toa Alta Municipio

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

Aftershocks so far

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

  1. 2.3 1 km ENE of Cayey, Puerto Rico
  2. 2.7 14 km NE of Arecibo, Puerto Rico
  3. 3.0 Puerto Rico region
  4. 3.3 49 km N of Tierras Nuevas Poniente, Puerto Rico
  5. 2.6 4 km NNE of Carrizales, Puerto Rico
  6. 2.5 17 km NNW of Brenas, Puerto Rico
  7. 2.6 Puerto Rico region
  8. 3.5 3 km WSW of Manatí, Puerto Rico
  9. 2.8 20 km N of Carrizales, Puerto Rico
  10. 2.5 7 km S of Orocovis, Puerto Rico
  11. 1.8 6 km SSW of Orocovis, Puerto Rico
  12. 3.2 Puerto Rico region
  13. 2.5 39 km N of Tierras Nuevas Poniente, Puerto Rico
  14. 2.3 8 km SSW of Orocovis, Puerto Rico
  15. 2.7 11 km N of Arecibo, 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.