QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Puerto Real, PR

No earthquake was likely felt in Puerto Real in the 24 hours to 4:29 pm AST (20:29 UTC). The last one was M 2.1, 10 km (6 mi) SE, at 11:57 pm AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Puerto Real

This page: a magnitude 2.1 earthquake was recorded 10 km (6 mi) west of Puerto Real, PR, at 4:49 pm AST on 21 December 2017 (20:49 UTC), 20 km deep.

USGS: 10 km W of Puerto Real, Puerto Rico

21 km (13 mi) SW of Mayagüez, PR · 134 km (83 mi) WSW of San Juan, PR

4:49 pm AST, Dec 21, 2017 · · 20 km deep · released about 43 lb of TNT

Every earthquake near Puerto Real Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cabo Rojo Municipio 14 kmHormigueros Municipio 19 kmSan Germán Municipio 26 kmLajas Municipio 28 kmAñasco Municipio 29 kmRincón Municipio 30 kmAguada Municipio 35 kmSabana Grande Municipio 36 kmLas Marías Municipio 37 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
4:49 pm AST on 21 December 2017 ()
Where
10 km (6 mi) west of Puerto Real, PR · earthquakes near Puerto Real
Magnitude
M 2.1 (md)
Depth
20 km below the surface
Felt
no reports yet
Nearest
Cabo Rojo Municipio, 14 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3247 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Puerto Real, 10 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: Boquerón, Cabo Rojo, Pole Ojea, Hormigueros, Monte Grande, Mayagüez.

How big was it?

This earthquake released about 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 4.3 on 2017-10-14 — about 2,000 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.3 6 km WNW of Aguadilla, Puerto Rico · 42 km N of this epicentre
  2. 5.8 4 km E of Moca, Puerto Rico · 43 km NNE of this epicentre
  3. 5.2 19 km SW of Stella, Puerto Rico · 16 km NW of this epicentre
  4. 5.1 21 km SW of Stella, Puerto Rico · 14 km NW 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 18.0733, -67.2845. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cabo Rojo Municipio, PR 14 km (9 mi) SE earthquakes near Cabo Rojo Municipio
Hormigueros Municipio, PR 19 km (12 mi) ENE earthquakes near Hormigueros Municipio
San Germán Municipio, PR 26 km (16 mi) E earthquakes near San Germán Municipio
Lajas Municipio, PR 28 km (17 mi) ESE earthquakes near Lajas Municipio
Añasco Municipio, PR 29 km (18 mi) NE earthquakes near Añasco Municipio
Rincón Municipio, PR 30 km (18 mi) N earthquakes near Rincón Municipio

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

Aftershocks so far

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

  1. 2.2 26 km W of Pole Ojea, Puerto Rico
  2. 1.8 16 km NNE of La Parguera, Puerto Rico
  3. 2.1 5 km W of Boquerón, Puerto Rico
  4. 2.2 6 km WSW of Puerto Real, Puerto Rico
  5. 2.9 17 km NNW of Rincón, Puerto Rico
  6. 2.1 2 km SW of La Parguera, Puerto Rico
  7. 2.8 Mona Passage
  8. 2.0 10 km SSE of Maria Antonia, Puerto Rico
  9. 1.9 1 km SSE of La Playa, Puerto Rico
  10. 1.6 20 km S of La Parguera, Puerto Rico
  11. 1.7 5 km NE of La Parguera, Puerto Rico
  12. 1.7 8 km S of La Parguera, Puerto Rico
  13. 2.0 5 km SSW of La Parguera, Puerto Rico
  14. 2.6 3 km WSW of Rincón, Puerto Rico
  15. 2.2 5 km NE of San Germán, 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.