QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near Cidra, PR

No earthquake was likely felt in Cidra in the 24 hours to 10:11 am AST (14:11 UTC). The last one was M 3.3, 44 km (27 mi) SW, at 8:40 am AST on 1 November 2026, estimated intensity II (weak) in town. Every earthquake near Cidra

This page: a magnitude 2.8 earthquake was recorded in Cidra, PR, at 12:57 am AST on 28 September 2023 (04:57 UTC), 75 km deep. 1 person has reported feeling it to USGS.

USGS: 1 km SSW of Cidra, Puerto Rico

29 km (18 mi) SSW of San Juan, PR · 15 km (9 mi) WSW of Caguas, PR

12:57 am AST, Sep 28, 2023 · · 75 km deep · released about 480 lb of TNT

Every earthquake near Cidra Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cidra Municipio 1 kmCayey Municipio 7 kmComerío Municipio 9 kmAguas Buenas Municipio 11 kmAibonito Municipio 11 kmCaguas Municipio 13 kmBarranquitas Municipio 16 kmNaranjito Municipio 17 kmSan Lorenzo Municipio 20 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
12:57 am AST on 28 September 2023 ()
Where
in Cidra, PR · earthquakes near Cidra
Magnitude
M 2.8 (md)
Depth
75 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Cidra Municipio, 1 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1028 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. 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: Parcelas La Milagrosa, Parcelas Nuevas, Cayey, Santa Clara, Sumidero, G. L. Garcia.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 500 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.1 3 km W of Aguas Buenas, Puerto Rico · 11 km NNE of this epicentre
  2. 5.0 3 km N of Brenas, Puerto Rico · 42 km NNW 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 18.1650, -66.1637. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cidra Municipio, PR 1 km (1 mi) NNE earthquakes near Cidra Municipio
Cayey Municipio, PR 7 km (4 mi) S earthquakes near Cayey Municipio
Comerío Municipio, PR 9 km (6 mi) NW earthquakes near Comerío Municipio
Aguas Buenas Municipio, PR 11 km (7 mi) NNE earthquakes near Aguas Buenas Municipio
Aibonito Municipio, PR 11 km (7 mi) WSW earthquakes near Aibonito Municipio
Caguas Municipio, PR 13 km (8 mi) ENE earthquakes near Caguas Municipio

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

Aftershocks so far

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

  1. 1.8 6 km SSW of Orocovis, Puerto Rico
  2. 2.0 Puerto Rico region
  3. 2.7 5 km SSE of Salinas, Puerto Rico
  4. 2.3 6 km SSE of Salinas, Puerto Rico
  5. 1.9 5 km SSE of Salinas, Puerto Rico
  6. 3.2 12 km SW of Santa Isabel, Puerto Rico
  7. 2.5 5 km WSW of Central Aguirre, Puerto Rico
  8. 2.4 5 km S of Salinas, Puerto Rico
  9. 3.2 Puerto Rico region
  10. 2.5 3 km SE of Jauca, Puerto Rico
  11. 2.5 6 km SSE of Jobos, Puerto Rico
  12. 2.2 8 km SSE of Jobos, Puerto Rico
  13. 2.2 6 km S of Jobos, Puerto Rico
  14. 3.2 8 km SSE of Jobos, Puerto Rico
  15. 1.9 Puerto Rico region

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.