QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

Earthquake near El Negro, PR

No earthquake was likely felt in El Negro in the 24 hours to 12:56 pm AST (16:56 UTC). The last one was M 2.2, 7 km (5 mi) SSE, at 2:59 pm AST on 4 November 2026, estimated intensity II (weak) in town. Every earthquake near El Negro

This page: a magnitude 2.7 earthquake was recorded 23 km (15 mi) east-southeast of El Negro, PR, at 8:07 am AST on 1 October 2021 (12:07 UTC), 18 km deep.

USGS: 23 km ESE of El Negro, Puerto Rico

67 km (42 mi) SE of San Juan, PR · 52 km (32 mi) SE of Caguas, PR

8:07 am AST, Oct 1, 2021 · · 18 km deep · released about 390 lb of TNT

Every earthquake near El Negro Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Yabucoa Municipio 25 kmHumacao Municipio 26 kmMaunabo Municipio 26 kmVieques Municipio 31 kmNaguabo Municipio 31 kmCeiba Municipio 35 kmLas Piedras Municipio 36 kmPatillas Municipio 36 kmSan Lorenzo Municipio 41 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
8:07 am AST on 1 October 2021 ()
Where
23 km (15 mi) east-southeast of El Negro, PR · earthquakes near El Negro
Magnitude
M 2.7 (md)
Depth
18 km below the surface
Felt
no reports yet
Nearest
Yabucoa Municipio, 25 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1867 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 El Negro, 23 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: Emajagua, Comunas, Esperanza, Candelero Arriba, Yabucoa, Punta Santiago.

How big was it?

This earthquake released about 390 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 39,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 28,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.5× the energy of this one
  4. This earthquake M 2.7 about 390 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 4.6 on 2016-12-05 — about 620 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 17.9431, -65.6536. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Yabucoa Municipio, PR 25 km (16 mi) WNW earthquakes near Yabucoa Municipio
Humacao Municipio, PR 26 km (16 mi) NNW earthquakes near Humacao Municipio
Maunabo Municipio, PR 26 km (16 mi) WNW earthquakes near Maunabo Municipio
Vieques Municipio, PR 31 km (19 mi) NE earthquakes near Vieques Municipio
Naguabo Municipio, PR 31 km (19 mi) NNW earthquakes near Naguabo Municipio
Ceiba Municipio, PR 35 km (22 mi) N earthquakes near Ceiba Municipio

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

Aftershocks so far

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

  1. 2.5 23 km S of Arroyo, Puerto Rico
  2. 2.0 5 km ESE of Jobos, Puerto Rico
  3. 3.0 54 km S of Emajagua, Puerto Rico
  4. 2.3 1 km WNW of Esperanza, Puerto Rico
  5. 2.5 22 km SSW of Esperanza, Puerto Rico
  6. 3.1 9 km WSW of Culebra, Puerto Rico
  7. 3.7 15 km SE of Esperanza, Puerto Rico
  8. 2.2 7 km SSE of Lamboglia, Puerto Rico
  9. 3.0 13 km SE of Esperanza, Puerto Rico
  10. 2.2 3 km N of Yaurel, Puerto Rico
  11. 3.0 2 km N of Yaurel, Puerto Rico
  12. 1.8 19 km SW of Esperanza, Puerto Rico
  13. 3.2 18 km SE of Esperanza, Puerto Rico
  14. 2.1 5 km SSE of Palmas, Puerto Rico
  15. 3.2 Puerto Rico region

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.