QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Humacao, PR

No earthquake was likely felt in Humacao in the 24 hours to 5:29 pm AST (21:29 UTC). The last one was M 4.1, 56 km (35 mi) ESE, at 5:44 am AST on 28 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near Humacao

This page: a magnitude 1.7 earthquake was recorded 38 km (23 mi) south-southeast of Humacao, PR, at 2:32 pm AST on 28 April 2017 (18:32 UTC), 16 km deep.

USGS: 30 km SE of El Negro, Puerto Rico

75 km (47 mi) SE of San Juan, PR · 59 km (37 mi) SE of Caguas, PR

2:32 pm AST, Apr 28, 2017 · · 16 km deep · released about 12 lb of TNT

Every earthquake near Humacao Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Maunabo Municipio 32 kmYabucoa Municipio 32 kmHumacao Municipio 34 kmVieques Municipio 36 kmNaguabo Municipio 40 kmPatillas Municipio 41 kmCeiba Municipio 43 kmLas Piedras Municipio 44 kmArroyo Municipio 45 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
2:32 pm AST on 28 April 2017 ()
Where
38 km (23 mi) south-southeast of Humacao, PR · earthquakes near Humacao
Magnitude
M 1.7 (md)
Depth
16 km below the surface
Felt
no reports yet
Nearest
Maunabo Municipio, 32 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3484 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 Humacao, 38 km away, the estimate is intensity I (not felt). 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 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 900,000× the energy of this one
  3. Around the size people start to feel M 3.0 80× the energy of this one
  4. This earthquake M 1.7 about 12 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 20,000 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 17.8668, -65.6295. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Maunabo Municipio, PR 32 km (20 mi) WNW earthquakes near Maunabo Municipio
Yabucoa Municipio, PR 32 km (20 mi) NW earthquakes near Yabucoa Municipio
Humacao Municipio, PR 34 km (21 mi) NNW earthquakes near Humacao Municipio
Vieques Municipio, PR 36 km (22 mi) NE earthquakes near Vieques Municipio
Naguabo Municipio, PR 40 km (25 mi) NNW earthquakes near Naguabo Municipio
Patillas Municipio, PR 41 km (25 mi) WNW earthquakes near Patillas Municipio

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

Aftershocks so far

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

  1. 2.5 26 km SE of El Negro, Puerto Rico
  2. 1.8 27 km SE of El Negro, Puerto Rico
  3. 2.3 21 km SSE of Arroyo, Puerto Rico
  4. 2.5 20 km S of Esperanza, Puerto Rico
  5. 2.0 26 km SE of El Negro, Puerto Rico
  6. 2.3 29 km SE of El Negro, Puerto Rico
  7. 2.1 27 km SE of El Negro, Puerto Rico
  8. 1.7 11 km SE of Esperanza, Puerto Rico
  9. 1.7 7 km ESE of Esperanza, Puerto Rico
  10. 1.8 17 km SSW of Esperanza, Puerto Rico
  11. 2.3 27 km SE of El Negro, Puerto Rico
  12. 1.9 6 km SSE of Punta Santiago, Puerto Rico
  13. 3.2 26 km SE of Esperanza, Puerto Rico
  14. 3.0 28 km SE of El Negro, Puerto Rico
  15. 2.2 15 km SE 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.