QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1md

Earthquake near Isabela, PR

No earthquake was likely felt in Isabela in the 24 hours to 6:01 pm AST (22:01 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 3.1 earthquake was recorded 45 km (28 mi) north-northeast of Isabela, PR, at 12:00 am AST on 27 September 2019 (04:00 UTC), 67 km deep. 10 people have reported feeling it to USGS.

USGS: 45 km NNE of Isabela, Puerto Rico

54 km (34 mi) NNW of Arecibo, PR · 107 km (67 mi) WNW of San Juan, PR

12:00 am AST, Sep 27, 2019 · · 67 km deep · released about 1,300 lb of TNT

Every earthquake near Isabela Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Isabela Municipio 47 kmQuebradillas Municipio 48 kmCamuy Municipio 51 kmAguadilla Municipio 52 kmHatillo Municipio 53 kmArecibo Municipio 59 kmMoca Municipio 60 kmBarceloneta Municipio 62 kmSan Sebastián Municipio 64 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
12:00 am AST on 27 September 2019 ()
Where
45 km (28 mi) north-northeast of Isabela, PR · earthquakes near Isabela
Magnitude
M 3.1 (md)
Depth
67 km below the surface
Felt
10 reports · strongest reported intensity III
Nearest
Isabela Municipio, 47 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2602 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, 45 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 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 6.0 on 2019-09-24 — about 23,000 times the energy of this one.

Before 2016, the USGS record lists 18 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.7 45 km N of San Antonio, Puerto Rico · 19 km W of this epicentre
  2. 7.1 24 km NNW of San Antonio, Puerto Rico · 35 km SW of this epicentre
  3. 6.4 61 km N of Hatillo, Puerto Rico · 21 km NE of this epicentre
  4. 6.1 15 km WNW of San Antonio, Puerto Rico · 50 km SW of this epicentre
  5. 6.1 18 km NNW of San Antonio, Puerto Rico · 39 km SW 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 18.9015, -66.9376. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Isabela Municipio, PR 47 km (29 mi) S earthquakes near Isabela Municipio
Quebradillas Municipio, PR 48 km (30 mi) S earthquakes near Quebradillas Municipio
Camuy Municipio, PR 51 km (32 mi) S earthquakes near Camuy Municipio
Aguadilla Municipio, PR 52 km (32 mi) SSW earthquakes near Aguadilla Municipio
Hatillo Municipio, PR 53 km (33 mi) SSE earthquakes near Hatillo Municipio
Arecibo Municipio, PR 59 km (37 mi) SSE earthquakes near Arecibo Municipio

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

Aftershocks so far

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

  1. 3.0 71 km NNW of San Antonio, Puerto Rico
  2. 2.8 53 km N of San Antonio, Puerto Rico
  3. 2.7 36 km NNE of Isabela, Puerto Rico
  4. 2.6 85 km N of San Antonio, Puerto Rico
  5. 2.8 62 km NNW of San Antonio, Puerto Rico
  6. 2.6 74 km NNW of San Antonio, Puerto Rico
  7. 2.6 52 km N of Isabela, Puerto Rico
  8. 3.0 80 km N of Isabela, Puerto Rico
  9. 2.1 49 km NW of San Antonio, Puerto Rico
  10. 2.7 77 km N of San Antonio, Puerto Rico
  11. 2.5 46 km NNE of Isabela, Puerto Rico
  12. 2.9 56 km N of San Antonio, Puerto Rico
  13. 2.4 72 km N of San Antonio, Puerto Rico
  14. 2.6 24 km N of San Antonio, Puerto Rico
  15. 3.0 67 km N of San Antonio, 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.