QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5md

Earthquake near Arecibo, PR

No earthquake was likely felt in Arecibo in the 24 hours to 10:14 am AST (14:14 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 3.5 earthquake was recorded 12 km (8 mi) north-northeast of Arecibo, PR, at 6:34 am AST on 20 March 2023 (10:34 UTC), 26 km deep. 7 people have reported feeling it to USGS.

USGS: 12 km NNE of Arecibo, Puerto Rico

15 km (9 mi) NNE of Arecibo, PR · 69 km (43 mi) WNW of San Juan, PR

6:34 am AST, Mar 20, 2023 · · 26 km deep · released about 2.3 tons of TNT

Every earthquake near Arecibo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Arecibo Municipio 17 kmBarceloneta Municipio 19 kmHatillo Municipio 19 kmCamuy Municipio 24 kmManatí Municipio 26 kmFlorida Municipio 27 kmQuebradillas Municipio 28 kmVega Baja Municipio 34 kmUtuado Municipio 35 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
6:34 am AST on 20 March 2023 ()
Where
12 km (8 mi) north-northeast of Arecibo, PR · earthquakes near Arecibo
Magnitude
M 3.5 (md)
Depth
26 km below the surface
Felt
7 reports · strongest reported intensity IV
Measured shaking
intensity II (ShakeMap)
Nearest
Arecibo Municipio, 17 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1265 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, people at rest would likely notice it out to about 55 km (34 mi) from the epicentre. In Arecibo, 12 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.

Likely felt in: Arecibo 12 km, intensity II · Hatillo 18 km, intensity II · Barceloneta 22 km, intensity II · Quebradillas 29 km, intensity II · Vega Baja 35 km, intensity II · Ciales 36 km, intensity II · Isabela 36 km, intensity II · Lares 37 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 2.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 72,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 3,200× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,300× the energy of this one
  4. This earthquake M 3.5 about 2.3 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 4.9× 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 4.4 on 2018-12-09 — about 26 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.8 12 km N of Garrochales, Puerto Rico · 13 km E of this epicentre
  2. 5.8 4 km E of Moca, Puerto Rico · 45 km WSW of this epicentre
  3. 5.0 3 km N of Brenas, Puerto Rico · 38 km ESE 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 18.5820, -66.6910. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Arecibo Municipio, PR 17 km (10 mi) S earthquakes near Arecibo Municipio
Barceloneta Municipio, PR 19 km (12 mi) SE earthquakes near Barceloneta Municipio
Hatillo Municipio, PR 19 km (12 mi) SW earthquakes near Hatillo Municipio
Camuy Municipio, PR 24 km (15 mi) SW earthquakes near Camuy Municipio
Manatí Municipio, PR 26 km (16 mi) SE earthquakes near Manatí Municipio
Florida Municipio, PR 27 km (17 mi) SSE earthquakes near Florida Municipio

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

Aftershocks so far

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

  1. 2.1 5 km S of Utuado, Puerto Rico
  2. 3.3 31 km N of Tierras Nuevas Poniente, Puerto Rico
  3. 3.3 7 km NNW of Brenas, Puerto Rico
  4. 2.2 4 km ENE of Maricao, Puerto Rico
  5. 3.2 1 km NE of Hatillo, Puerto Rico
  6. 2.0 8 km S of Lares, Puerto Rico
  7. 2.3 8 km W of Orocovis, Puerto Rico
  8. 2.9 7 km NE of Maricao, Puerto Rico
  9. 3.1 Puerto Rico region
  10. 2.7 4 km SSE of Ciales, Puerto Rico
  11. 2.6 5 km NE of Animas, Puerto Rico
  12. 3.3 7 km NNE of Dorado, Puerto Rico
  13. 2.8 Puerto Rico region
  14. 2.3 5 km WNW of Orocovis, Puerto Rico
  15. 2.9 30 km N of Arecibo, 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.