QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

Earthquake near Arroyo, PR

No earthquake was likely felt in Arroyo in the 24 hours to 10:10 am AST (14:10 UTC). The last one was M 3.3, 39 km (24 mi) WSW, at 8:40 am AST on 1 November 2026, estimated intensity II (weak) in town. Every earthquake near Arroyo

This page: a magnitude 2.6 earthquake was recorded 5 km (3 mi) east-southeast of Arroyo, PR, at 12:37 am AST on 21 September 2023 (04:37 UTC), 38 km deep.

USGS: Puerto Rico region

51 km (32 mi) S of San Juan, PR · 31 km (20 mi) S of Caguas, PR

12:37 am AST, Sep 21, 2023 · · 38 km deep · released about 260 lb of TNT

Every earthquake near Arroyo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Arroyo Municipio 4 kmPatillas Municipio 6 kmGuayama Municipio 13 kmMaunabo Municipio 14 kmYabucoa Municipio 21 kmCayey Municipio 22 kmSan Lorenzo Municipio 22 kmSalinas Municipio 26 kmCaguas Municipio 29 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
12:37 am AST on 21 September 2023 ()
Where
5 km (3 mi) east-southeast of Arroyo, PR · earthquakes near Arroyo
Magnitude
M 2.6 (md)
Depth
38 km below the surface
Felt
no reports yet
Nearest
Arroyo Municipio, 4 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1147 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 Arroyo, 5 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: Palmas, Lamboglia, Patillas, Buena Vista, Corazón, Yaurel.

How big was it?

This earthquake released about 260 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 59,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 42,000× the energy of this one
  3. Around the size people start to feel M 3.0 3.7× the energy of this one
  4. This earthquake M 2.6 about 260 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 in our catalogue was M 4.6 on 2016-12-05 — about 930 times the energy of this one.

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 17.9505, -66.0163. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Arroyo Municipio, PR 4 km (2 mi) NW earthquakes near Arroyo Municipio
Patillas Municipio, PR 6 km (4 mi) NNE earthquakes near Patillas Municipio
Guayama Municipio, PR 13 km (8 mi) WNW earthquakes near Guayama Municipio
Maunabo Municipio, PR 14 km (9 mi) ENE earthquakes near Maunabo Municipio
Yabucoa Municipio, PR 21 km (13 mi) NE earthquakes near Yabucoa Municipio
Cayey Municipio, PR 22 km (14 mi) NW earthquakes near Cayey Municipio

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

Aftershocks so far

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

  1. 2.2 6 km S of Jobos, Puerto Rico
  2. 3.2 8 km SSE of Jobos, Puerto Rico
  3. 1.9 Puerto Rico region
  4. 2.3 6 km SSE of Jobos, Puerto Rico
  5. 2.1 6 km SSE of Jobos, Puerto Rico
  6. 2.3 5 km SSE of Jobos, Puerto Rico
  7. 2.1 7 km SSE of Jobos, Puerto Rico
  8. 2.8 8 km SSE of Jobos, Puerto Rico
  9. 3.2 4 km SSE of Salinas, Puerto Rico
  10. 1.9 7 km SSE of Salinas, Puerto Rico
  11. 3.1 4 km S of Salinas, Puerto Rico
  12. 3.5 3 km S of Salinas, Puerto Rico
  13. 2.3 8 km SSW of Orocovis, Puerto Rico
  14. 2.5 17 km S of Central Aguirre, Puerto Rico
  15. 2.1 7 km NNW of Coamo, 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.