QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

Earthquake near Ciales, PR

No earthquake was likely felt in Ciales in the 24 hours to 11:28 am AST (15:28 UTC). The last one was M 4.8, 67 km (42 mi) SW, at 9:19 am AST on 18 September 2026, estimated intensity III (weak) in town; 86 felt reports to USGS. Every earthquake near Ciales

This page: a magnitude 1.8 earthquake was recorded 9 km (6 mi) south-southwest of Ciales, PR, at 2:59 am AST on 28 January 2019 (06:59 UTC), 28 km deep.

USGS: 8 km SSW of Ciales, Puerto Rico

49 km (30 mi) WSW of San Juan, PR · 32 km (20 mi) NNE of Ponce, PR

2:59 am AST, Jan 28, 2019 · · 28 km deep · released about 15 lb of TNT

Every earthquake near Ciales Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Ciales Municipio 4 kmOrocovis Municipio 9 kmJayuya Municipio 11 kmMorovis Municipio 11 kmFlorida Municipio 13 kmVillalba Municipio 15 kmCorozal Municipio 19 kmManatí Municipio 20 kmUtuado Municipio 21 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
2:59 am AST on 28 January 2019 ()
Where
9 km (6 mi) south-southwest of Ciales, PR · earthquakes near Ciales
Magnitude
M 1.8 (md)
Depth
28 km below the surface
Felt
no reports yet
Nearest
Ciales Municipio, 4 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2844 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 Ciales, 9 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: Jayuya, Barahona, Franquez, Morovis, Florida, Estancias de Florida.

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 730,000× the energy of this one
  3. Around the size people start to feel M 3.0 65× the energy of this one
  4. This earthquake M 1.8 about 15 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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 · 34 km N of this epicentre
  2. 5.1 3 km W of Aguas Buenas, Puerto Rico · 39 km E of this epicentre
  3. 5.0 3 km N of Brenas, Puerto Rico · 31 km NNE 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 18.2638, -66.5040. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Ciales Municipio, PR 4 km (2 mi) NNW earthquakes near Ciales Municipio
Orocovis Municipio, PR 9 km (5 mi) SE earthquakes near Orocovis Municipio
Jayuya Municipio, PR 11 km (7 mi) SW earthquakes near Jayuya Municipio
Morovis Municipio, PR 11 km (7 mi) NE earthquakes near Morovis Municipio
Florida Municipio, PR 13 km (8 mi) NNW earthquakes near Florida Municipio
Villalba Municipio, PR 15 km (9 mi) SSE earthquakes near Villalba Municipio

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

Aftershocks so far

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

  1. 2.3 1 km NNW of Indios, Puerto Rico
  2. 2.2 2 km ESE of Las Marías, Puerto Rico
  3. 2.2 3 km ESE of Las Marías, Puerto Rico
  4. 1.7 2 km ESE of Las Marías, Puerto Rico
  5. 3.8 1 km ESE of Las Marías, Puerto Rico
  6. 1.9 4 km N of Palmarejo, Puerto Rico
  7. 2.4 7 km NNE of Hatillo, Puerto Rico
  8. 1.9 1 km ENE of El Ojo, Puerto Rico
  9. 1.7 Puerto Rico region
  10. 1.9 2 km E of Magas Arriba, Puerto Rico
  11. 2.0 2 km ESE of Magas Arriba, Puerto Rico
  12. 1.7 6 km SSE of Indios, Puerto Rico
  13. 2.6 10 km N of Hatillo, Puerto Rico
  14. 1.5 Puerto Rico region
  15. 2.0 0 km SSE of Playita Cortada, 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.