QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

Earthquake near Humacao, PR

No earthquake was likely felt in Humacao in the 24 hours to 12:50 pm AST (16:50 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 38 km (23 mi) southeast of Humacao, PR, at 4:09 am AST on 16 August 2018 (08:09 UTC), 5.0 km deep.

USGS: Puerto Rico region

75 km (47 mi) SE of San Juan, PR

4:09 am AST, Aug 16, 2018 · · 5.0 km deep · released about 98 lb of TNT

Every earthquake near Humacao Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Vieques Municipio 30 kmHumacao Municipio 34 kmYabucoa Municipio 34 kmMaunabo Municipio 35 kmNaguabo Municipio 38 kmCeiba Municipio 39 kmLas Piedras Municipio 44 kmPatillas Municipio 44 kmArroyo Municipio 49 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
4:09 am AST on 16 August 2018 ()
Where
38 km (23 mi) southeast of Humacao, PR · earthquakes near Humacao
Magnitude
M 2.3 (md)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Vieques Municipio, 30 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3009 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 20 km (12 mi) from the epicentre. In Humacao, 38 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: Esperanza.

How big was it?

This earthquake released about 98 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.

  1. Mineral, Virginia 2011 M 5.8 150,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 110,000× the energy of this one
  3. Around the size people start to feel M 3.0 9.8× the energy of this one
  4. This earthquake M 2.3 about 98 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 in our catalogue was M 4.6 on 2016-12-05 — about 2,500 times the energy of this one.

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 17.9020, -65.5840. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Vieques Municipio, PR 30 km (18 mi) NNE earthquakes near Vieques Municipio
Humacao Municipio, PR 34 km (21 mi) NW earthquakes near Humacao Municipio
Yabucoa Municipio, PR 34 km (21 mi) WNW earthquakes near Yabucoa Municipio
Maunabo Municipio, PR 35 km (22 mi) WNW earthquakes near Maunabo Municipio
Naguabo Municipio, PR 38 km (24 mi) NNW earthquakes near Naguabo Municipio
Ceiba Municipio, PR 39 km (24 mi) N earthquakes near Ceiba Municipio

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

Aftershocks so far

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

  1. 2.3 9 km SSE of Arroyo, Puerto Rico
  2. 2.2 29 km SSW of Esperanza, Puerto Rico
  3. 2.1 5 km SSE of Arroyo, Puerto Rico
  4. 2.1 22 km SSE of Lamboglia, Puerto Rico
  5. 1.6 5 km SE of Arroyo, Puerto Rico
  6. 1.8 11 km S of Emajagua, Puerto Rico
  7. 2.1 23 km S of Emajagua, Puerto Rico
  8. 1.8 9 km SSW of Emajagua, Puerto Rico
  9. 2.2 24 km SE of Emajagua, Puerto Rico
  10. 3.0 65 km S of Esperanza, Puerto Rico
  11. 3.4 38 km SE of Esperanza, Puerto Rico
  12. 2.0 27 km S of Emajagua, Puerto Rico
  13. 1.8 8 km SE of Esperanza, Puerto Rico
  14. 1.9 9 km S of Emajagua, Puerto Rico
  15. 2.1 10 km S of Emajagua, 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.