QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

Earthquake near Isabela, PR

No earthquake was likely felt in Isabela in the 24 hours to 8:01 pm AST (00:01 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 2.7 earthquake was recorded 36 km (22 mi) north-northwest of Isabela, PR, at 4:57 am AST on 22 October 2018 (08:57 UTC), 29 km deep.

USGS: 35 km N of San Antonio, Puerto Rico

57 km (35 mi) NW of Arecibo, PR · 120 km (75 mi) WNW of San Juan, PR

4:57 am AST, Oct 22, 2018 · · 29 km deep · released about 310 lb of TNT

Every earthquake near Isabela Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aguadilla Municipio 37 kmIsabela Municipio 38 kmQuebradillas Municipio 43 kmMoca Municipio 48 kmAguada Municipio 49 kmCamuy Municipio 49 kmHatillo Municipio 53 kmRincón Municipio 54 kmSan Sebastián Municipio 56 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
4:57 am AST on 22 October 2018 ()
Where
36 km (22 mi) north-northwest of Isabela, PR · earthquakes near Isabela
Magnitude
M 2.7 (md)
Depth
29 km below the surface
Felt
no reports yet
Nearest
Aguadilla Municipio, 37 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2943 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 Isabela, 36 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.

How big was it?

This earthquake released about 310 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 50,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 35,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.1× the energy of this one
  4. This earthquake M 2.7 about 310 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 280 times the energy of this one.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.7 45 km N of San Antonio, Puerto Rico · 11 km N of this epicentre
  2. 7.1 24 km NNW of San Antonio, Puerto Rico · 14 km SSW of this epicentre
  3. 6.4 32 km NW of Aguadilla, Puerto Rico · 35 km SW of this epicentre
  4. 6.4 61 km N of Hatillo, Puerto Rico · 42 km NE of this epicentre
  5. 6.3 6 km WNW of Aguadilla, Puerto Rico · 42 km SSW 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 18.8093, -67.1206. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguadilla Municipio, PR 37 km (23 mi) S earthquakes near Aguadilla Municipio
Isabela Municipio, PR 38 km (24 mi) SSE earthquakes near Isabela Municipio
Quebradillas Municipio, PR 43 km (27 mi) SSE earthquakes near Quebradillas Municipio
Moca Municipio, PR 48 km (30 mi) S earthquakes near Moca Municipio
Aguada Municipio, PR 49 km (30 mi) S earthquakes near Aguada Municipio
Camuy Municipio, PR 49 km (30 mi) SE earthquakes near Camuy Municipio

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

Aftershocks so far

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

  1. 2.3 42 km NW of San Antonio, Puerto Rico
  2. 2.8 47 km NW of San Antonio, Puerto Rico
  3. 2.5 47 km N of Isabela, Puerto Rico
  4. 2.3 53 km NW of San Antonio, Puerto Rico
  5. 2.5 28 km NW of Rincón, Puerto Rico
  6. 2.5 38 km WNW of San Antonio, Puerto Rico
  7. 2.2 9 km NNW of Camuy, Puerto Rico
  8. 2.4 15 km N of Carrizales, Puerto Rico
  9. 2.8 43 km NNW of San Antonio, Puerto Rico
  10. 2.1 19 km NNW of Camuy, Puerto Rico
  11. 2.8 56 km N of Carrizales, Puerto Rico
  12. 2.4 20 km N of Carrizales, Puerto Rico
  13. 2.7 54 km NNW of San Antonio, Puerto Rico
  14. 2.5 77 km NNW of San Antonio, Puerto Rico
  15. 2.5 39 km NW of Rincón, 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.