QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Earthquake near Isabel Segunda, PR

No earthquake was likely felt in Isabel Segunda in the 24 hours to 8:41 pm AST (00:41 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 2.9 earthquake was recorded 36 km (22 mi) east-southeast of Isabel Segunda, PR, at 7:28 pm AST on 4 September 2018 (23:28 UTC), 24 km deep.

USGS: 36 km ESE of Isabel Segunda, Puerto Rico

7:28 pm AST, Sep 4, 2018 · · 24 km deep · released about 610 lb of TNT

Every earthquake near Isabel Segunda Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Vieques Municipio 34 kmCulebra Municipio 39 kmCeiba Municipio 58 kmFajardo Municipio 63 kmNaguabo Municipio 67 kmHumacao Municipio 70 kmLuquillo Municipio 72 kmYabucoa Municipio 77 kmLas Piedras Municipio 80 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
7:28 pm AST on 4 September 2018 ()
Where
36 km (22 mi) east-southeast of Isabel Segunda, PR · earthquakes near Isabel Segunda
Magnitude
M 2.9 (md)
Depth
24 km below the surface
Felt
no reports yet
Nearest
Vieques Municipio, 34 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2976 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 19 km (12 mi) from the epicentre. In Isabel Segunda, 36 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.

How big was it?

This earthquake released about 610 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 25,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 18,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.6× the energy of this one
  4. This earthquake M 2.9 about 610 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 one earthquake of M5 or more within 50 km:

  1. 5.0 29 km S of Cruz Bay, U.S. Virgin Islands · 40 km E 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 18.0186, -65.1311. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Vieques Municipio, PR 34 km (21 mi) WNW earthquakes near Vieques Municipio
Culebra Municipio, PR 39 km (24 mi) NNW earthquakes near Culebra Municipio
Ceiba Municipio, PR 58 km (36 mi) WNW earthquakes near Ceiba Municipio
Fajardo Municipio, PR 63 km (39 mi) NW earthquakes near Fajardo Municipio
Naguabo Municipio, PR 67 km (42 mi) WNW earthquakes near Naguabo Municipio
Humacao Municipio, PR 70 km (44 mi) W earthquakes near Humacao Municipio

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

Aftershocks so far

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

  1. 2.2 Virgin Islands
  2. 2.2 18 km SSW of Charlotte Amalie, U.S. Virgin Islands
  3. 2.3 18 km WNW of Saint Croix, U.S. Virgin Islands
  4. 1.9 24 km S of Esperanza, Puerto Rico
  5. 2.6 29 km ESE of Esperanza, Puerto Rico
  6. 2.6 11 km WNW of Isabel Segunda, Puerto Rico
  7. 2.2 16 km S of Esperanza, Puerto Rico
  8. 2.4 30 km SSE of Esperanza, Puerto Rico
  9. 2.3 10 km WNW of Culebra, Puerto Rico
  10. 3.1 8 km W of Charlotte Amalie, U.S. Virgin Islands
  11. 3.0 36 km SE of Esperanza, Puerto Rico
  12. 2.3 21 km SE of Isabel Segunda, Puerto Rico
  13. 3.1 12 km E of Culebra, Puerto Rico
  14. 3.0 10 km WNW of Charlotte Amalie, U.S. Virgin Islands
  15. 1.8 23 km SSE of Esperanza, 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.