QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1md

Earthquake near Aguadilla, PR

No earthquake was likely felt in Aguadilla in the 24 hours to 7:57 pm AST (23:57 UTC). The last one was M 3.5, 4 km (3 mi) SE, at 12:03 am AST on 6 November 2026, estimated intensity II (weak) in town. Every earthquake near Aguadilla

This page: a magnitude 3.1 earthquake was recorded 7 km (5 mi) west-northwest of Aguadilla, PR, at 3:34 pm AST on 24 July 2021 (19:34 UTC), 19 km deep. 1 person has reported feeling it to USGS.

USGS: 7 km WNW of Aguadilla, Puerto Rico

30 km (19 mi) NNW of Mayagüez, PR · 121 km (75 mi) W of San Juan, PR

3:34 pm AST, Jul 24, 2021 · · 19 km deep · released about 1,300 lb of TNT

Every earthquake near Aguadilla Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aguadilla Municipio 7 kmAguada Municipio 10 kmRincón Municipio 14 kmMoca Municipio 17 kmIsabela Municipio 21 kmAñasco Municipio 21 kmSan Sebastián Municipio 30 kmQuebradillas Municipio 30 kmLas Marías Municipio 36 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
3:34 pm AST on 24 July 2021 ()
Where
7 km (5 mi) west-northwest of Aguadilla, PR · earthquakes near Aguadilla
Magnitude
M 3.1 (md)
Depth
19 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Aguadilla Municipio, 7 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1866 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 37 km (23 mi) from the epicentre. In Aguadilla, 7 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.

Likely felt in: Aguadilla 7 km, intensity II · Aguada 10 km, intensity II · Rafael Hernandez 14 km, intensity II · Rincón 14 km, intensity II · Isabela 20 km, intensity II · San Sebastián 27 km, intensity II · Quebradillas 29 km, intensity II · Mayagüez 30 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 260,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 12,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 8,200× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× more

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 2019-09-05 — about 65 times the energy of this one.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 24 km NNW of San Antonio, Puerto Rico · 26 km N of this epicentre
  2. 6.4 32 km NW of Aguadilla, Puerto Rico · 25 km NW of this epicentre
  3. 6.3 6 km WNW of Aguadilla, Puerto Rico · 3 km S of this epicentre
  4. 6.1 15 km WNW of San Antonio, Puerto Rico · 10 km NNW of this epicentre
  5. 6.1 18 km NNW of San Antonio, Puerto Rico · 20 km N 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 18.4636, -67.2126. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguadilla Municipio, PR 7 km (5 mi) ENE earthquakes near Aguadilla Municipio
Aguada Municipio, PR 10 km (6 mi) SSE earthquakes near Aguada Municipio
Rincón Municipio, PR 14 km (9 mi) SSW earthquakes near Rincón Municipio
Moca Municipio, PR 17 km (11 mi) SE earthquakes near Moca Municipio
Isabela Municipio, PR 21 km (13 mi) E earthquakes near Isabela Municipio
Añasco Municipio, PR 21 km (13 mi) SSE earthquakes near Añasco Municipio

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

Aftershocks so far

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

  1. 3.2 35 km NNW of San Antonio, Puerto Rico
  2. 3.1 46 km NW of San Antonio, Puerto Rico
  3. 2.5 6 km SW of Las Marías, Puerto Rico
  4. 3.1 36 km NNW of San Antonio, Puerto Rico
  5. 3.0 1 km W of Cabo Rojo, Puerto Rico
  6. 3.4 22 km NNE of Isabela, Puerto Rico
  7. 3.1 9 km S of Lares, Puerto Rico
  8. 2.7 26 km NW of Rincón, Puerto Rico
  9. 2.9 8 km W of Hormigueros, Puerto Rico
  10. 3.3 43 km NNW of San Antonio, Puerto Rico
  11. 2.9 4 km N of Sabana Grande, Puerto Rico
  12. 2.7 16 km W of Puerto Real, Puerto Rico
  13. 3.5 31 km NNW of San Antonio, Puerto Rico
  14. 2.9 27 km NW of San Antonio, Puerto Rico
  15. 2.1 6 km E of Mayagüez, 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.