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 6:04 pm AST (22:04 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 in Ciales, PR, at 11:28 am AST on 18 May 2017 (15:28 UTC), 22 km deep.

USGS: 0 km NNE of Ciales, Puerto Rico

43 km (27 mi) W of San Juan, PR · 31 km (19 mi) ESE of Arecibo, PR

11:28 am AST, May 18, 2017 · · 22 km deep · released about 17 lb of TNT

Every earthquake near Ciales Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Morovis Municipio 6 kmCiales Municipio 7 kmFlorida Municipio 11 kmManatí Municipio 12 kmOrocovis Municipio 14 kmVega Baja Municipio 15 kmCorozal Municipio 15 kmBarceloneta Municipio 17 kmVega Alta 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
11:28 am AST on 18 May 2017 ()
Where
in Ciales, PR · earthquakes near Ciales
Magnitude
M 1.8 (md)
Depth
22 km below the surface
Felt
no reports yet
Nearest
Morovis Municipio, 6 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3462 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. 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: Barahona, Franquez, Morovis, Florida, Manatí, Miranda.

How big was it?

This earthquake released about 17 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 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× the energy of this one
  4. This earthquake M 1.8 about 17 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 · 27 km NNW of this epicentre
  2. 5.1 3 km W of Aguas Buenas, Puerto Rico · 36 km ESE of this epicentre
  3. 5.0 3 km N of Brenas, Puerto Rico · 22 km NE 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 18.3385, -66.4680. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Morovis Municipio, PR 6 km (3 mi) ESE earthquakes near Morovis Municipio
Ciales Municipio, PR 7 km (4 mi) SW earthquakes near Ciales Municipio
Florida Municipio, PR 11 km (7 mi) WNW earthquakes near Florida Municipio
Manatí Municipio, PR 12 km (8 mi) NNW earthquakes near Manatí Municipio
Orocovis Municipio, PR 14 km (9 mi) SSE earthquakes near Orocovis Municipio
Vega Baja Municipio, PR 15 km (9 mi) NNE earthquakes near Vega Baja Municipio

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

Aftershocks so far

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

  1. 2.1 0 km SSW of Cayuco, Puerto Rico
  2. 2.1 4 km SSE of Cayey, Puerto Rico
  3. 2.8 17 km N of Carrizales, Puerto Rico
  4. 3.1 1 km NW of Bayamón, Puerto Rico
  5. 2.3 10 km S of Lares, Puerto Rico
  6. 2.7 15 km NNE of Hatillo, Puerto Rico
  7. 2.3 1 km S of Río Lajas, Puerto Rico
  8. 2.5 10 km WSW of Adjuntas, Puerto Rico
  9. 2.6 21 km NNE of Dorado, Puerto Rico
  10. 3.1 5 km ESE of Cataño, Puerto Rico
  11. 2.9 3 km N of Trujillo Alto, Puerto Rico
  12. 1.7 7 km ESE of Las Marías, Puerto Rico
  13. 2.1 9 km ESE of Adjuntas, Puerto Rico
  14. 2.7 20 km N of Brenas, Puerto Rico
  15. 2.2 26 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.