QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Earthquake near Santa Barbara, PR

No earthquake was likely felt in Santa Barbara in the 24 hours to 11:29 am AST (15:29 UTC). The last one was M 4.1, 78 km (49 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 Santa Barbara

This page: a magnitude 2.9 earthquake was recorded 4 km (3 mi) north-northwest of Santa Barbara, PR, at 4:38 am AST on 17 December 2023 (08:38 UTC), 83 km deep.

USGS: 4 km NNW of Santa Barbara, Puerto Rico

6 km (3 mi) ENE of Carolina, PR

4:38 am AST, Dec 17, 2023 · · 83 km deep · released about 720 lb of TNT

Every earthquake near Santa Barbara Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Loíza Municipio 2 kmCarolina Municipio 6 kmCanóvanas Municipio 12 kmTrujillo Alto Municipio 13 kmSan Juan Municipio 15 kmRío Grande Municipio 15 kmGurabo Municipio 18 kmGuaynabo Municipio 22 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
4:38 am AST on 17 December 2023 ()
Where
4 km (3 mi) north-northwest of Santa Barbara, PR · earthquakes near Santa Barbara
Magnitude
M 2.9 (md)
Depth
83 km below the surface
Felt
no reports yet
Nearest
Loíza Municipio, 2 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1060 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 Santa Barbara, 4 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: Loíza, Carolina, San Isidro, Canovanas, Suárez, La Dolores.

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 4.1 on 2019-05-02 — about 59 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 · 29 km SW of this epicentre
  2. 5.0 3 km N of Brenas, Puerto Rico · 44 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 18.4308, -65.9303. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Loíza Municipio, PR 2 km (1 mi) NW earthquakes near Loíza Municipio
Carolina Municipio, PR 6 km (3 mi) SW earthquakes near Carolina Municipio
Canóvanas Municipio, PR 12 km (8 mi) SSE earthquakes near Canóvanas Municipio
Trujillo Alto Municipio, PR 13 km (8 mi) SW earthquakes near Trujillo Alto Municipio
San Juan Municipio, PR 15 km (9 mi) W earthquakes near San Juan Municipio
Río Grande Municipio, PR 15 km (9 mi) ESE earthquakes near Río Grande Municipio

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

Aftershocks so far

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

  1. 2.7 12 km N of Brenas, Puerto Rico
  2. 2.6 3 km NNE of Dorado, Puerto Rico
  3. 3.1 2 km NNW of Juncos, Puerto Rico
  4. 2.6 1 km W of Punta Santiago, Puerto Rico
  5. 2.5 5 km SSE of G. L. Garcia, Puerto Rico
  6. 2.3 4 km WSW of Parcelas La Milagrosa, Puerto Rico
  7. 1.9 7 km ESE of G. L. Garcia, Puerto Rico
  8. 2.9 10 km NNW of San Juan, Puerto Rico
  9. 2.7 1 km W of G. L. Garcia, Puerto Rico
  10. 2.1 4 km ENE of Orocovis, Puerto Rico
  11. 2.8 4 km S of Bajandas, Puerto Rico
  12. 2.6 4 km S of Bajandas, Puerto Rico
  13. 2.7 4 km S of Bajandas, Puerto Rico
  14. 3.7 4 km SW of Ramos, Puerto Rico
  15. 2.3 6 km SSE of Bajandas, 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.