QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Isabel Segunda, PR

No earthquake was likely felt in Isabel Segunda in the 24 hours to 3:33 pm AST (19:33 UTC). The last one was M 2.9, 26 km (16 mi) SSE, at 12:08 pm AST on 29 October 2026, estimated intensity II (weak) in town. Every earthquake near Isabel Segunda

This page: a magnitude 2.4 earthquake was recorded 17 km (11 mi) south-southeast of Isabel Segunda, PR, at 6:26 pm AST on 31 August 2017 (22:26 UTC), 30 km deep.

USGS: Puerto Rico region

86 km (53 mi) ESE of San Juan, PR

6:26 pm AST, Aug 31, 2017 · · 30 km deep · released about 100 lb of TNT

Every earthquake near Isabel Segunda Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Vieques Municipio 14 kmCulebra Municipio 35 kmCeiba Municipio 38 kmNaguabo Municipio 45 kmHumacao Municipio 47 kmFajardo Municipio 48 kmYabucoa Municipio 53 kmLuquillo Municipio 54 kmMaunabo Municipio 56 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
6:26 pm AST on 31 August 2017 ()
Where
17 km (11 mi) south-southeast of Isabel Segunda, PR · earthquakes near Isabel Segunda
Magnitude
M 2.4 (md)
Depth
30 km below the surface
Felt
no reports yet
Nearest
Vieques Municipio, 14 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3270 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 Isabel Segunda, 17 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: Esperanza.

How big was it?

This earthquake released about 100 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 150,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 110,000× the energy of this one
  3. Around the size people start to feel M 3.0 9.4× the energy of this one
  4. This earthquake M 2.4 about 100 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 in our catalogue was M 4.3 on 2016-09-02 — about 840 times the energy of this one.

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 18.0131, -65.3640. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Vieques Municipio, PR 14 km (9 mi) NNW earthquakes near Vieques Municipio
Culebra Municipio, PR 35 km (22 mi) N earthquakes near Culebra Municipio
Ceiba Municipio, PR 38 km (24 mi) NW earthquakes near Ceiba Municipio
Naguabo Municipio, PR 45 km (28 mi) WNW earthquakes near Naguabo Municipio
Humacao Municipio, PR 47 km (29 mi) WNW earthquakes near Humacao Municipio
Fajardo Municipio, PR 48 km (30 mi) NNW earthquakes near Fajardo Municipio

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

Aftershocks so far

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

  1. 2.9 36 km ESE of Isabel Segunda, Puerto Rico
  2. 2.0 33 km S of Esperanza, Puerto Rico
  3. 2.5 13 km WSW of Esperanza, Puerto Rico
  4. 2.0 25 km SE of El Negro, Puerto Rico
  5. 3.1 22 km SW of Esperanza, Puerto Rico
  6. 2.3 Puerto Rico region
  7. 2.5 8 km NNW of Isabel Segunda, Puerto Rico
  8. 2.9 6 km S of Esperanza, Puerto Rico
  9. 2.3 2 km SW of Bajandas, Puerto Rico
  10. 2.9 23 km S of Esperanza, Puerto Rico
  11. 2.4 9 km SSE of Punta Santiago, Puerto Rico
  12. 2.7 16 km SSW of Esperanza, Puerto Rico
  13. 2.8 31 km SSW of Charlotte Amalie, U.S. Virgin Islands
  14. 3.0 22 km S of Charlotte Amalie, U.S. Virgin Islands
  15. 2.9 8 km SE of Culebra, 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.