QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Cayey, PR

No earthquake was likely felt in Cayey in the 24 hours to 4:23 pm AST (20:23 UTC). The last one was M 3.3, 38 km (24 mi) SW, at 8:40 am AST on 1 November 2026, estimated intensity II (weak) in town. Every earthquake near Cayey

This page: a magnitude 2.1 earthquake was recorded 4 km (2 mi) east-southeast of Cayey, PR, at 7:52 am AST on 17 September 2018 (11:52 UTC), 25 km deep.

USGS: 3 km ESE of Cayey, Puerto Rico

35 km (22 mi) SSW of San Juan, PR · 18 km (11 mi) SSW of Caguas, PR

7:52 am AST, Sep 17, 2018 · · 25 km deep · released about 49 lb of TNT

Every earthquake near Cayey Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cayey Municipio 2 kmCidra Municipio 9 kmGuayama Municipio 13 kmAibonito Municipio 14 kmCaguas Municipio 16 kmArroyo Municipio 17 kmComerío Municipio 17 kmSan Lorenzo Municipio 18 kmAguas Buenas Municipio 18 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
7:52 am AST on 17 September 2018 ()
Where
4 km (2 mi) east-southeast of Cayey, PR · earthquakes near Cayey
Magnitude
M 2.1 (md)
Depth
25 km below the surface
Felt
no reports yet
Nearest
Cayey Municipio, 2 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2906 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Cayey, 4 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: G. L. Garcia, Parcelas Nuevas, La Plena, Cidra, Parcelas La Milagrosa, Olimpo.

How big was it?

This earthquake released about 49 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 310,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 220,000× the energy of this one
  3. Around the size people start to feel M 3.0 19× the energy of this one
  4. This earthquake M 2.1 about 49 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 4.6 on 2016-12-05 — about 4,900 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.1 3 km W of Aguas Buenas, Puerto Rico · 18 km N 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 18.0946, -66.1341. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cayey Municipio, PR 2 km (1 mi) WNW earthquakes near Cayey Municipio
Cidra Municipio, PR 9 km (6 mi) NNW earthquakes near Cidra Municipio
Guayama Municipio, PR 13 km (8 mi) S earthquakes near Guayama Municipio
Aibonito Municipio, PR 14 km (9 mi) WNW earthquakes near Aibonito Municipio
Caguas Municipio, PR 16 km (10 mi) NE earthquakes near Caguas Municipio
Arroyo Municipio, PR 17 km (10 mi) SE earthquakes near Arroyo Municipio

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

Aftershocks so far

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

  1. 2.0 7 km SE of Arroyo, Puerto Rico
  2. 2.1 4 km ESE of Palmarejo, Puerto Rico
  3. 2.0 Puerto Rico region
  4. 2.0 3 km SSW of Jauca, Puerto Rico
  5. 2.3 2 km SSW of Jauca, Puerto Rico
  6. 2.0 2 km SSW of Jauca, Puerto Rico
  7. 2.0 2 km SE of Santa Isabel, Puerto Rico
  8. 2.1 1 km SSE of G. L. Garcia, Puerto Rico
  9. 2.1 6 km NNW of Loíza, Puerto Rico
  10. 1.6 3 km NNW of Playita Cortada, Puerto Rico
  11. 2.5 11 km S of Emajagua, Puerto Rico
  12. 1.9 2 km S of Las Ochenta, Puerto Rico
  13. 2.4 5 km SSW of Central Aguirre, Puerto Rico
  14. 1.6 9 km W of Orocovis, Puerto Rico
  15. 1.5 1 km SE of Santa Isabel, 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.