QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

Earthquake near San Sebastián, PR

No earthquake was likely felt in San Sebastián in the 24 hours to 10:49 am AST (14:49 UTC). The last one was M 3.4, 50 km (31 mi) N, at 9:00 pm AST on 27 October 2026, estimated intensity II (weak) in town. Every earthquake near San Sebastián

This page: a magnitude 2.5 earthquake was recorded 5 km (3 mi) west of San Sebastián, PR, at 8:53 pm AST on 5 March 2018 (00:53 UTC), 16 km deep.

USGS: 4 km W of San Sebastián, Puerto Rico

18 km (11 mi) NE of Mayagüez, PR · 103 km (64 mi) W of San Juan, PR

8:53 pm AST, Mar 5, 2018 · · 16 km deep · released about 180 lb of TNT

Every earthquake near San Sebastián Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Moca Municipio 7 kmSan Sebastián Municipio 7 kmAñasco Municipio 11 kmLas Marías Municipio 13 kmAguada Municipio 17 kmIsabela Municipio 17 kmLares Municipio 19 kmQuebradillas Municipio 19 kmAguadilla 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
8:53 pm AST on 5 March 2018 ()
Where
5 km (3 mi) west of San Sebastián, PR · earthquakes near San Sebastián
Magnitude
M 2.5 (md)
Depth
16 km below the surface
Felt
no reports yet
Nearest
Moca Municipio, 7 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3172 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, people at rest would likely notice it out to about 16 km (10 mi) from the epicentre. In San Sebastián, 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.

Likely felt in: San Sebastián 5 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 180 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 86,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 61,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.4× the energy of this one
  4. This earthquake M 2.5 about 180 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 4.3 on 2017-10-14 — about 480 times the energy of this one.

Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 24 km NNW of San Antonio, Puerto Rico · 44 km NNW of this epicentre
  2. 6.4 32 km NW of Aguadilla, Puerto Rico · 48 km NW of this epicentre
  3. 6.3 6 km WNW of Aguadilla, Puerto Rico · 22 km WNW of this epicentre
  4. 6.1 15 km WNW of San Antonio, Puerto Rico · 32 km NW of this epicentre
  5. 6.1 18 km NNW of San Antonio, Puerto Rico · 37 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 18.3316, -67.0358. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Moca Municipio, PR 7 km (4 mi) NW earthquakes near Moca Municipio
San Sebastián Municipio, PR 7 km (4 mi) E earthquakes near San Sebastián Municipio
Añasco Municipio, PR 11 km (7 mi) WSW earthquakes near Añasco Municipio
Las Marías Municipio, PR 13 km (8 mi) SSE earthquakes near Las Marías Municipio
Aguada Municipio, PR 17 km (10 mi) WNW earthquakes near Aguada Municipio
Isabela Municipio, PR 17 km (11 mi) N earthquakes near Isabela Municipio

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

Aftershocks so far

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

  1. 2.0 1 km NNE of Sabana Eneas, Puerto Rico
  2. 2.4 16 km N of Hatillo, Puerto Rico
  3. 2.1 8 km SSE of La Parguera, Puerto Rico
  4. 2.1 7 km SSE of Guánica, Puerto Rico
  5. 1.9 0 km W of Sabana Grande, Puerto Rico
  6. 2.6 19 km WSW of Stella, Puerto Rico
  7. 2.9 22 km NNE of Isabela, Puerto Rico
  8. 2.5 17 km N of Carrizales, Puerto Rico
  9. 2.1 4 km ESE of Boquerón, Puerto Rico
  10. 2.0 6 km NW of Puerto Real, Puerto Rico
  11. 2.5 3 km NNW of Lluveras, Puerto Rico
  12. 1.8 3 km WSW of Sabana Grande, Puerto Rico
  13. 2.1 24 km WNW of Puerto Real, Puerto Rico
  14. 2.0 7 km SSW of Indios, Puerto Rico
  15. 2.0 1 km N of La Playa, 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.