QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near San Juan, PR

No earthquake was likely felt in San Juan in the 24 hours to 12:54 pm AST (16:54 UTC). The last one was M 4.1, 99 km (62 mi) SE, at 5:44 am AST on 28 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near San Juan

This page: a magnitude 2.8 earthquake was recorded 9 km (6 mi) east-northeast of San Juan, PR, at 2:00 am AST on 9 April 2018 (06:00 UTC), 106 km deep.

USGS: 9 km ENE of San Juan, Puerto Rico

12 km (7 mi) NNE of San Juan, PR · 12 km (7 mi) NNW of Carolina, PR

2:00 am AST, Apr 9, 2018 · · 106 km deep · released about 510 lb of TNT

Every earthquake near San Juan Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Juan Municipio 10 kmLoíza Municipio 11 kmCarolina Municipio 14 kmCataño Municipio 14 kmToa Baja Municipio 18 kmTrujillo Alto Municipio 19 kmGuaynabo Municipio 20 kmBayamón Municipio 23 kmCanóvanas Municipio 25 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
2:00 am AST on 9 April 2018 ()
Where
9 km (6 mi) east-northeast of San Juan, PR · earthquakes near San Juan
Magnitude
M 2.8 (md)
Depth
106 km below the surface
Felt
no reports yet
Nearest
San Juan Municipio, 10 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3138 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 San Juan, 9 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, Carolina, Trujillo Alto, Santa Barbara, Levittown.

How big was it?

This earthquake released about 510 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 30,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 21,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.9× the energy of this one
  4. This earthquake M 2.8 about 510 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 · 30 km SSW of this epicentre
  2. 5.0 3 km N of Brenas, Puerto Rico · 33 km W 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 18.5055, -66.0288. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Juan Municipio, PR 10 km (6 mi) SSW earthquakes near San Juan Municipio
Loíza Municipio, PR 11 km (7 mi) SE earthquakes near Loíza Municipio
Carolina Municipio, PR 14 km (8 mi) SSE earthquakes near Carolina Municipio
Cataño Municipio, PR 14 km (9 mi) WSW earthquakes near Cataño Municipio
Toa Baja Municipio, PR 18 km (11 mi) WSW earthquakes near Toa Baja Municipio
Trujillo Alto Municipio, PR 19 km (12 mi) S earthquakes near Trujillo Alto Municipio

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

Aftershocks so far

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

  1. 1.6 12 km NNW of Brenas, Puerto Rico
  2. 2.9 20 km NNW of Brenas, Puerto Rico
  3. 1.7 1 km SE of Bayamón, Puerto Rico
  4. 2.8 4 km SE of Cataño, Puerto Rico
  5. 2.3 4 km N of Brenas, Puerto Rico
  6. 2.0 3 km SW of Guaynabo, Puerto Rico
  7. 2.6 31 km N of San Juan, Puerto Rico
  8. 2.5 33 km NNW of Brenas, Puerto Rico
  9. 2.4 2 km SW of Sumidero, Puerto Rico
  10. 2.5 4 km NNE of Guaynabo, Puerto Rico
  11. 1.9 5 km ENE of G. L. Garcia, Puerto Rico
  12. 2.0 6 km NE of Comerío, Puerto Rico
  13. 2.3 2 km SSW of Bayamón, Puerto Rico
  14. 2.5 12 km NNE of Brenas, Puerto Rico
  15. 1.7 3 km ESE 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.