QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5Md

Earthquake near Trujillo Alto, PR

No earthquake was likely felt in Trujillo Alto in the 24 hours to 8:42 pm AST (00:42 UTC). The last one was M 4.1, 83 km (52 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 Trujillo Alto

This page: a magnitude 2.5 earthquake was recorded 7 km (4 mi) north-northwest of Trujillo Alto, PR, at 12:47 pm AST on 18 October 2016 (16:47 UTC), 117 km deep.

USGS: 7 km NNW of Trujillo Alto, Puerto Rico

in San Juan, PR

12:47 pm AST, Oct 18, 2016 · · 117 km deep · released about 170 lb of TNT

Every earthquake near Trujillo Alto Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Juan Municipio 3 kmCarolina Municipio 8 kmTrujillo Alto Municipio 9 kmGuaynabo Municipio 11 kmLoíza Municipio 11 kmCataño Municipio 12 kmBayamón Municipio 15 kmGurabo Municipio 17 kmToa Baja 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
12:47 pm AST on 18 October 2016 ()
Where
7 km (4 mi) north-northwest of Trujillo Alto, PR · earthquakes near Trujillo Alto
Magnitude
M 2.5 (Md)
Depth
117 km below the surface
Felt
no reports yet
Nearest
San Juan Municipio, 3 km WNW
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 Trujillo Alto, 7 km away, the estimate is intensity I (not felt). 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: Eleanor Roosevelt, Cataño, San Juan, Guaynabo, Carolina, Bayamón.

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

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 · 19 km SSW of this epicentre
  2. 5.0 3 km N of Brenas, Puerto Rico · 33 km WNW 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 18.4097, -66.0412. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Juan Municipio, PR 3 km (2 mi) WNW earthquakes near San Juan Municipio
Carolina Municipio, PR 8 km (5 mi) E earthquakes near Carolina Municipio
Trujillo Alto Municipio, PR 9 km (6 mi) SSE earthquakes near Trujillo Alto Municipio
Guaynabo Municipio, PR 11 km (7 mi) SW earthquakes near Guaynabo Municipio
Loíza Municipio, PR 11 km (7 mi) ENE earthquakes near Loíza Municipio
Cataño Municipio, PR 12 km (7 mi) WNW earthquakes near Cataño 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. 2.1 2 km SW of Canovanas, Puerto Rico
  2. 2.2 1 km ESE of Cidra, Puerto Rico
  3. 3.2 4 km NNW of Bairoa, Puerto Rico
  4. 2.6 1 km WSW of Campo Rico, Puerto Rico
  5. 2.5 3 km W of Guaynabo, Puerto Rico
  6. 2.1 0 km N of Pastos, Puerto Rico
  7. 2.9 38 km N of San Juan, Puerto Rico
  8. 2.5 1 km WSW of Bairoa, Puerto Rico
  9. 3.1 1 km WSW of Sabana, Puerto Rico
  10. 2.3 6 km S of Punta Santiago, Puerto Rico
  11. 3.0 7 km N of Vieques, Puerto Rico
  12. 2.9 14 km N of Brenas, Puerto Rico
  13. 2.9 5 km NNE of Orocovis, Puerto Rico
  14. 2.2 9 km N of Loíza, Puerto Rico
  15. 1.8 3 km ESE of Cayey, 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.