QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

Earthquake near Arecibo, PR

No earthquake was likely felt in Arecibo in the 24 hours to 6:11 am AST (10:11 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 2.3 earthquake was recorded 10 km (6 mi) north-northwest of Arecibo, PR, at 7:04 am AST on 18 December 2018 (11:04 UTC), 20 km deep.

USGS: 10 km NNW of Arecibo, Puerto Rico

12 km (7 mi) N of Arecibo, PR · 73 km (46 mi) WNW of San Juan, PR

7:04 am AST, Dec 18, 2018 · · 20 km deep · released about 91 lb of TNT

Every earthquake near Arecibo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Hatillo Municipio 15 kmArecibo Municipio 16 kmCamuy Municipio 18 kmBarceloneta Municipio 22 kmQuebradillas Municipio 22 kmFlorida Municipio 28 kmManatí Municipio 29 kmIsabela Municipio 30 kmUtuado Municipio 32 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
7:04 am AST on 18 December 2018 ()
Where
10 km (6 mi) north-northwest of Arecibo, PR · earthquakes near Arecibo
Magnitude
M 2.3 (md)
Depth
20 km below the surface
Felt
no reports yet
Nearest
Hatillo Municipio, 15 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2820 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 1 km (1 mi) from the epicentre. In Arecibo, 10 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.

Earthquakes near other towns within 30 km: Carrizales, Corcovado, Hatillo, Camuy, Rafael Gonzalez, Bajadero.

How big was it?

This earthquake released about 91 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 170,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 120,000× the energy of this one
  3. Around the size people start to feel M 3.0 10× the energy of this one
  4. This earthquake M 2.3 about 91 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 4.4 on 2018-12-09 — about 1,300 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 24 km NNW of San Antonio, Puerto Rico · 50 km WNW of this epicentre
  2. 6.1 18 km NNW of San Antonio, Puerto Rico · 47 km W of this epicentre
  3. 5.8 12 km N of Garrochales, Puerto Rico · 19 km E of this epicentre
  4. 5.8 4 km E of Moca, Puerto Rico · 39 km WSW of this epicentre
  5. 5.3 28 km NNW of San Antonio, Puerto Rico · 49 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 18.5605, -66.7408. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Hatillo Municipio, PR 15 km (9 mi) SSW earthquakes near Hatillo Municipio
Arecibo Municipio, PR 16 km (10 mi) SSE earthquakes near Arecibo Municipio
Camuy Municipio, PR 18 km (11 mi) SW earthquakes near Camuy Municipio
Barceloneta Municipio, PR 22 km (13 mi) ESE earthquakes near Barceloneta Municipio
Quebradillas Municipio, PR 22 km (14 mi) WSW earthquakes near Quebradillas Municipio
Florida Municipio, PR 28 km (18 mi) SE earthquakes near Florida Municipio

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

Aftershocks so far

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

  1. 1.8 3 km W of Rafael Capo, Puerto Rico
  2. 2.0 3 km SW of Adjuntas, Puerto Rico
  3. 2.2 4 km ENE of Isabela, Puerto Rico
  4. 2.9 13 km NNW of Brenas, Puerto Rico
  5. 1.8 1 km SE of Piedra Gorda, Puerto Rico
  6. 2.9 49 km N of Hatillo, Puerto Rico
  7. 2.4 13 km N of Carrizales, Puerto Rico
  8. 1.5 18 km NNE of Tierras Nuevas Poniente, Puerto Rico
  9. 2.5 12 km N of Brenas, Puerto Rico
  10. 2.6 32 km N of Garrochales, Puerto Rico
  11. 2.4 34 km N of Arecibo, Puerto Rico
  12. 2.5 18 km NNW of Camuy, Puerto Rico
  13. 1.6 19 km N of Tierras Nuevas Poniente, Puerto Rico
  14. 1.6 5 km W of Jayuya, Puerto Rico
  15. 1.9 7 km WSW of Adjuntas, 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.