QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Puerto Rico region

Yes. A magnitude 2.9 earthquake was recorded in the Puerto Rico region, at 7:05 pm AST on 18 December 2019 (23:05 UTC), 11 km deep.

· 11 km deep · released about 590 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Loíza Municipio 100 kmSan Juan Municipio 105 kmCataño Municipio 105 kmToa Baja Municipio 106 kmCarolina Municipio 106 kmRío Grande Municipio 107 kmDorado Municipio 107 kmLuquillo Municipio 108 kmFajardo Municipio 108 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
Magnitude
M 2.9 (md)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Loíza Municipio, 100 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2440 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, people at rest would likely notice it out to about 28 km (17 mi) from the epicentre. 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 590 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 26,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 18,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.6× the energy of this one
  4. This earthquake M 2.9 about 590 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 in our catalogue was M 4.0 on 2019-06-21 — about 51 times the energy of this one.

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 19.3346, -65.8118. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Loíza Municipio, PR 100 km (62 mi) S earthquakes near Loíza Municipio
San Juan Municipio, PR 105 km (65 mi) SSW earthquakes near San Juan Municipio
Cataño Municipio, PR 105 km (65 mi) SSW earthquakes near Cataño Municipio
Toa Baja Municipio, PR 106 km (66 mi) SSW earthquakes near Toa Baja Municipio
Carolina Municipio, PR 106 km (66 mi) S earthquakes near Carolina Municipio
Río Grande Municipio, PR 107 km (66 mi) S earthquakes near Río Grande Municipio

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

Aftershocks so far

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

  1. 3.1 77 km N of Brenas, Puerto Rico
  2. 3.4 105 km N of San Juan, Puerto Rico
  3. 3.5 132 km NNE of Suárez, Puerto Rico
  4. 3.5 116 km NNE of Suárez, Puerto Rico
  5. 3.6 130 km NNE of Suárez, Puerto Rico
  6. 3.5 119 km N of San Juan, Puerto Rico
  7. 3.5 118 km N of Brenas, Puerto Rico
  8. 3.4 67 km NNE of San Juan, Puerto Rico
  9. 3.4 101 km NNE of Suárez, Puerto Rico
  10. 3.5 106 km NNE of Vieques, Puerto Rico
  11. 2.6 Puerto Rico region
  12. 3.7 128 km NNE of Vieques, Puerto Rico
  13. 3.4 120 km NNE of Vieques, Puerto Rico
  14. 2.7 124 km NNE of Vieques, Puerto Rico
  15. 3.7 124 km NNE of Vieques, 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.