QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Earthquake near Arecibo, PR

No earthquake was likely felt in Arecibo in the 24 hours to 12:53 pm AST (16:53 UTC). The last one was M 3.4, 49 km (31 mi) NW, at 9:00 pm AST on 27 October 2026, estimated intensity II (weak) in town. Every earthquake near Arecibo

This page: a magnitude 2.9 earthquake was recorded 43 km (26 mi) north-northwest of Arecibo, PR, at 4:45 pm AST on 1 October 2017 (20:45 UTC), 71 km deep.

USGS: 36 km N of Camuy, Puerto Rico

99 km (62 mi) WNW of San Juan, PR · 43 km (27 mi) NNW of Arecibo, PR

4:45 pm AST, Oct 1, 2017 · · 71 km deep · released about 780 lb of TNT

Every earthquake near Arecibo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Isabela Municipio 39 kmQuebradillas Municipio 39 kmCamuy Municipio 41 kmHatillo Municipio 43 kmAguadilla Municipio 45 kmArecibo Municipio 48 kmMoca Municipio 52 kmBarceloneta Municipio 52 kmSan Sebastián Municipio 54 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
4:45 pm AST on 1 October 2017 ()
Where
43 km (26 mi) north-northwest of Arecibo, PR · earthquakes near Arecibo
Magnitude
M 2.9 (md)
Depth
71 km below the surface
Felt
no reports yet
Nearest
Isabela Municipio, 39 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3313 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 Arecibo, 43 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 780 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 19,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 14,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.2× the energy of this one
  4. This earthquake M 2.9 about 780 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 4.7 on 2017-07-17 — about 380 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 · 25 km WNW of this epicentre
  2. 7.1 24 km NNW of San Antonio, Puerto Rico · 33 km WSW of this epicentre
  3. 6.4 61 km N of Hatillo, Puerto Rico · 27 km NNE of this epicentre
  4. 6.1 15 km WNW of San Antonio, Puerto Rico · 46 km SW of this epicentre
  5. 6.1 18 km NNW of San Antonio, Puerto Rico · 35 km WSW 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 18.8130, -66.9000. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Isabela Municipio, PR 39 km (24 mi) SSW earthquakes near Isabela Municipio
Quebradillas Municipio, PR 39 km (24 mi) S earthquakes near Quebradillas Municipio
Camuy Municipio, PR 41 km (26 mi) S earthquakes near Camuy Municipio
Hatillo Municipio, PR 43 km (27 mi) SSE earthquakes near Hatillo Municipio
Aguadilla Municipio, PR 45 km (28 mi) SW earthquakes near Aguadilla Municipio
Arecibo Municipio, PR 48 km (30 mi) SSE earthquakes near Arecibo Municipio

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

Aftershocks so far

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

  1. 3.0 65 km N of Isabela, Puerto Rico
  2. 3.1 53 km N of Isabela, Puerto Rico
  3. 2.9 55 km NNW of San Antonio, Puerto Rico
  4. 2.9 42 km N of Camuy, Puerto Rico
  5. 2.8 50 km N of Isabela, Puerto Rico
  6. 2.4 15 km NNE of Hatillo, Puerto Rico
  7. 2.9 40 km NW of San Antonio, Puerto Rico
  8. 2.9 48 km NNW of San Antonio, Puerto Rico
  9. 3.1 Puerto Rico region
  10. 2.9 39 km N of San Antonio, Puerto Rico
  11. 2.6 31 km N of San Antonio, Puerto Rico
  12. 3.0 68 km NNE of Arecibo, Puerto Rico
  13. 2.7 19 km NW of San Antonio, Puerto Rico
  14. 3.2 42 km NNW of San Antonio, Puerto Rico
  15. 2.6 50 km NW 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.