QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3md

Earthquake near Isabel Segunda, PR

No earthquake was likely felt in Isabel Segunda in the 24 hours to 9:34 am AST (13:34 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 3.3 earthquake was recorded 37 km (23 mi) south of Isabel Segunda, PR, at 12:51 am AST on 21 June 2025 (04:51 UTC), 19 km deep.

USGS: 31 km SSE of Esperanza, Puerto Rico

97 km (60 mi) SE of San Juan, PR

12:51 am AST, Jun 21, 2025 · · 19 km deep · released about 1.3 tons of TNT

Every earthquake near Isabel Segunda Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Vieques Municipio 34 kmCeiba Municipio 54 kmHumacao Municipio 55 kmCulebra Municipio 56 kmYabucoa Municipio 57 kmNaguabo Municipio 57 kmMaunabo Municipio 58 kmLas Piedras Municipio 66 kmFajardo Municipio 66 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
12:51 am AST on 21 June 2025 ()
Where
37 km (23 mi) south of Isabel Segunda, PR · earthquakes near Isabel Segunda
Magnitude
M 3.3 (md)
Depth
19 km below the surface
Felt
no reports yet
Nearest
Vieques Municipio, 34 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 508 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 48 km (30 mi) from the epicentre. In Isabel Segunda, 37 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: Esperanza 32 km, intensity II · Isabel Segunda 37 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 130,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,800× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,100× the energy of this one
  4. This earthquake M 3.3 about 1.3 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.7× more

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 4.8 on 2021-10-08 — about 180 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 17.8242, -65.3803. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Vieques Municipio, PR 34 km (21 mi) N earthquakes near Vieques Municipio
Ceiba Municipio, PR 54 km (34 mi) NNW earthquakes near Ceiba Municipio
Humacao Municipio, PR 55 km (34 mi) NW earthquakes near Humacao Municipio
Culebra Municipio, PR 56 km (35 mi) N earthquakes near Culebra Municipio
Yabucoa Municipio, PR 57 km (35 mi) WNW earthquakes near Yabucoa Municipio
Naguabo Municipio, PR 57 km (35 mi) NW earthquakes near Naguabo Municipio

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

Aftershocks so far

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

  1. 2.7 24 km SE of Emajagua, Puerto Rico
  2. 2.1 10 km E of El Negro, Puerto Rico
  3. 3.2 11 km SSE of Punta Santiago, Puerto Rico
  4. 3.0 6 km SE of Isabel Segunda, Puerto Rico
  5. 2.6 14 km SE of Esperanza, Puerto Rico
  6. 2.4 7 km WNW of Esperanza, Puerto Rico
  7. 2.7 28 km SSW of Esperanza, Puerto Rico
  8. 3.0 14 km SE of Isabel Segunda, Puerto Rico
  9. 2.6 15 km WSW of Esperanza, Puerto Rico
  10. 2.5 19 km S of Esperanza, Puerto Rico
  11. 2.5 11 km S of Esperanza, Puerto Rico
  12. 2.7 21 km SSE of Emajagua, Puerto Rico
  13. 3.2 35 km SE of Esperanza, Puerto Rico
  14. 2.9 17 km SW of Esperanza, Puerto Rico
  15. 2.9 28 km SE of El Negro, 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.