Earthquake near Humacao, PR

No earthquake was likely felt in Humacao in the 24 hours to 11:12 pm AST (03:12 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 2.3 earthquake was recorded 40 km (25 mi) south-southeast of Humacao, PR, at 11:51 am AST on 4 September 2016 (15:51 UTC), 17 km deep.

USGS: 31 km SE of Emajagua, Puerto Rico

77 km (48 mi) SE of San Juan, PR

11:51 am AST, Sep 4, 2016 · 2016-09-04 15:51 UTC · 17 km deep · released about 85 lb of TNT

Every earthquake near Humacao Felt it? Tell USGS Check my area

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: 11:51 am AST on 4 September 2016 (2016-09-04 15:51 UTC)
Where: 40 km (25 mi) south-southeast of Humacao, PR · earthquakes near Humacao
Magnitude: M 2.3 (Md)
Depth: 17 km below the surface
Felt: no reports yet
Nearest: Maunabo Municipio, 33 km WNW
Status: Reviewed by a seismologist

USGS · last changed by USGS 3720 days ago · we first saw it 3720 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 10 km (6 mi) from the epicentre. In Humacao, 40 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 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
Magna, Utah 2020 M 5.7 130,000× the energy of this one
Around the size people start to feel M 3.0 11× the energy of this one
This earthquake M 2.3 about 85 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 4.3 on 2016-09-02 — about 1,000 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

5.3 68 km SSE of Emajagua, Puerto Rico · 50 km S of this epicentre Aug 1, 1993

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

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Nearby places

Place	Distance	Direction from the epicentre
Maunabo Municipio, PR	33 km (20 mi)	WNW	earthquakes near Maunabo Municipio
Yabucoa Municipio, PR	34 km (21 mi)	NW	earthquakes near Yabucoa Municipio
Humacao Municipio, PR	36 km (23 mi)	NNW	earthquakes near Humacao Municipio
Vieques Municipio, PR	39 km (24 mi)	NE	earthquakes near Vieques Municipio
Patillas Municipio, PR	41 km (25 mi)	WNW	earthquakes near Patillas Municipio
Naguabo Municipio, PR	43 km (26 mi)	NNW	earthquakes near Naguabo Municipio

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

Aftershocks so far

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

2.4 22 km SSE of Esperanza, Puerto Rico 07:28 UTC
2.2 11 km SE of Esperanza, Puerto Rico 07:15 UTC
2.6 26 km SE of El Negro, Puerto Rico 02:39 UTC
2.3 15 km SE of Esperanza, Puerto Rico 21:51 UTC
2.2 2 km NNE of Candelero Arriba, Puerto Rico 10:58 UTC
2.5 29 km SSW of Esperanza, Puerto Rico 12:05 UTC
2.3 Puerto Rico region 11:06 UTC
2.3 29 km SE of El Negro, Puerto Rico 09:20 UTC
1.9 29 km SE of El Negro, Puerto Rico 05:42 UTC
2.6 12 km SE of Esperanza, Puerto Rico 04:28 UTC
2.5 30 km SE of El Negro, Puerto Rico 02:28 UTC
1.7 29 km SE of El Negro, Puerto Rico 01:46 UTC
2.4 29 km SE of El Negro, Puerto Rico 23:49 UTC
2.0 30 km S of Esperanza, Puerto Rico 17:55 UTC
1.9 12 km SE of Esperanza, Puerto Rico 16:20 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 03:12 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

The official USGS event page — the source of record for every value above
Did you feel it? Report it to USGS — reports go to USGS, not to us
ShakeMap for this event, when USGS has produced one

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.