QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Isabela, PR

No earthquake was likely felt in Isabela in the 24 hours to 5:48 pm AST (21:48 UTC). The last one was M 3.4, 31 km (19 mi) N, at 9:00 pm AST on 27 October 2026, estimated intensity II (weak) in town. Every earthquake near Isabela

This page: a magnitude 2.4 earthquake was recorded 2 km (1 mi) east-northeast of Isabela, PR, at 3:20 pm AST on 22 July 2018 (19:20 UTC), 91 km deep.

USGS: 2 km ENE of Isabela, Puerto Rico

100 km (62 mi) W of San Juan, PR · 29 km (18 mi) WNW of Arecibo, PR

3:20 pm AST, Jul 22, 2018 · · 91 km deep · released about 130 lb of TNT

Every earthquake near Isabela Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Isabela Municipio 3 kmQuebradillas Municipio 9 kmAguadilla Municipio 15 kmCamuy Municipio 16 kmMoca Municipio 16 kmSan Sebastián Municipio 20 kmHatillo Municipio 23 kmAguada Municipio 24 kmAñasco Municipio 28 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
3:20 pm AST on 22 July 2018 ()
Where
2 km (1 mi) east-northeast of Isabela, PR · earthquakes near Isabela
Magnitude
M 2.4 (md)
Depth
91 km below the surface
Felt
no reports yet
Nearest
Isabela Municipio, 3 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2960 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 Isabela, 2 km away, the estimate is intensity I (not felt). 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: Mora, Quebradillas, Rafael Hernandez, Aceitunas, Cacao, Piedra Gorda.

How big was it?

This earthquake released about 130 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 110,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 80,000× the energy of this one
  3. Around the size people start to feel M 3.0 7.2× the energy of this one
  4. This earthquake M 2.4 about 130 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 640 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. 7.7 45 km N of San Antonio, Puerto Rico · 46 km NNW of this epicentre
  2. 7.1 24 km NNW of San Antonio, Puerto Rico · 29 km NW of this epicentre
  3. 6.4 32 km NW of Aguadilla, Puerto Rico · 42 km WNW of this epicentre
  4. 6.3 6 km WNW of Aguadilla, Puerto Rico · 23 km WSW of this epicentre
  5. 6.1 15 km WNW of San Antonio, Puerto Rico · 25 km WNW 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 18.5066, -67.0028. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Isabela Municipio, PR 3 km (2 mi) SSW earthquakes near Isabela Municipio
Quebradillas Municipio, PR 9 km (6 mi) ESE earthquakes near Quebradillas Municipio
Aguadilla Municipio, PR 15 km (9 mi) W earthquakes near Aguadilla Municipio
Camuy Municipio, PR 16 km (10 mi) ESE earthquakes near Camuy Municipio
Moca Municipio, PR 16 km (10 mi) SSW earthquakes near Moca Municipio
San Sebastián Municipio, PR 20 km (12 mi) S earthquakes near San Sebastián Municipio

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

Aftershocks so far

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

  1. 2.2 1 km SSE of Adjuntas, Puerto Rico
  2. 1.6 3 km SW of Adjuntas, Puerto Rico
  3. 2.1 3 km E of Hormigueros, Puerto Rico
  4. 2.5 4 km N of San Germán, Puerto Rico
  5. 2.7 39 km NW of Aguadilla, Puerto Rico
  6. 2.4 4 km S of Stella, Puerto Rico
  7. 2.9 43 km N of Isabela, Puerto Rico
  8. 2.2 9 km NNE of San Antonio, Puerto Rico
  9. 2.3 6 km SW of Las Marías, Puerto Rico
  10. 2.5 23 km N of Carrizales, Puerto Rico
  11. 1.8 3 km SSE of Mayagüez, Puerto Rico
  12. 2.8 32 km NNW of San Antonio, Puerto Rico
  13. 1.8 2 km W of La Playa, Puerto Rico
  14. 1.5 3 km NNW of Sabana Grande, Puerto Rico
  15. 2.5 12 km NW of Aguadilla, 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.