QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Earthquake near San Juan, PR

No earthquake was likely felt in San Juan in the 24 hours to 10:21 am AST (14:21 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 2.9 earthquake was recorded 43 km (27 mi) north of San Juan, PR, at 9:07 am AST on 15 December 2023 (13:07 UTC), 64 km deep. 1 person has reported feeling it to USGS.

USGS: 42 km N of San Juan, Puerto Rico

50 km (31 mi) N of San Juan, PR

9:07 am AST, Dec 15, 2023 · · 64 km deep · released about 720 lb of TNT

Every earthquake near San Juan Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Toa Baja Municipio 46 kmCataño Municipio 46 kmDorado Municipio 46 kmLoíza Municipio 48 kmSan Juan Municipio 48 kmCarolina Municipio 52 kmVega Alta Municipio 53 kmVega Baja Municipio 55 kmBayamón Municipio 57 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
9:07 am AST on 15 December 2023 ()
Where
43 km (27 mi) north of San Juan, PR · earthquakes near San Juan
Magnitude
M 2.9 (md)
Depth
64 km below the surface
Felt
1 report · strongest reported intensity I
Nearest
Toa Baja Municipio, 46 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1062 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, 43 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.

How big was it?

This earthquake released about 720 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 21,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 15,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.3× the energy of this one
  4. This earthquake M 2.9 about 720 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 660 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.5 64 km N of Tierras Nuevas Poniente, Puerto Rico · 46 km WNW of this epicentre
  2. 5.1 66 km N of Brenas, Puerto Rico · 38 km NW of this epicentre
  3. 5.0 3 km N of Brenas, Puerto Rico · 47 km SW 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 18.8543, -66.0895. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Toa Baja Municipio, PR 46 km (28 mi) SSW earthquakes near Toa Baja Municipio
Cataño Municipio, PR 46 km (29 mi) S earthquakes near Cataño Municipio
Dorado Municipio, PR 46 km (29 mi) SSW earthquakes near Dorado Municipio
Loíza Municipio, PR 48 km (30 mi) SSE earthquakes near Loíza Municipio
San Juan Municipio, PR 48 km (30 mi) S earthquakes near San Juan Municipio
Carolina Municipio, PR 52 km (33 mi) SSE earthquakes near Carolina Municipio

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

Aftershocks so far

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

  1. 3.1 18 km NNW of Brenas, Puerto Rico
  2. 3.0 51 km N of Tierras Nuevas Poniente, Puerto Rico
  3. 3.3 68 km N of Brenas, Puerto Rico
  4. 3.4 74 km N of Suárez, Puerto Rico
  5. 3.4 70 km N of Suárez, Puerto Rico
  6. 3.0 5 km NW of San Juan, Puerto Rico
  7. 2.9 34 km N of San Juan, Puerto Rico
  8. 3.2 37 km NNE of Vieques, Puerto Rico
  9. 3.4 29 km N of Tierras Nuevas Poniente, Puerto Rico
  10. 2.7 12 km N of Brenas, Puerto Rico
  11. 3.2 69 km N of Tierras Nuevas Poniente, Puerto Rico
  12. 2.8 69 km N of San Juan, Puerto Rico
  13. 2.6 3 km NNE of Dorado, Puerto Rico
  14. 3.1 52 km N of Brenas, Puerto Rico
  15. 3.0 69 km N of Brenas, 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.