QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

Earthquake near Humacao, PR

No earthquake was likely felt in Humacao in the 24 hours to 5:24 pm AST (21:24 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 1.8 earthquake was recorded 2 km (1 mi) west-northwest of Humacao, PR, at 3:52 am AST on 27 August 2019 (07:52 UTC), 70 km deep.

USGS: 2 km WNW of Humacao, Puerto Rico

36 km (22 mi) SE of San Juan, PR · 22 km (14 mi) ESE of Caguas, PR

3:52 am AST, Aug 27, 2019 · · 70 km deep · released about 17 lb of TNT

Every earthquake near Humacao Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Las Piedras Municipio 4 kmHumacao Municipio 7 kmJuncos Municipio 10 kmYabucoa Municipio 11 kmNaguabo Municipio 13 kmSan Lorenzo Municipio 14 kmMaunabo Municipio 18 kmGurabo Municipio 19 kmCanóvanas Municipio 20 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
3:52 am AST on 27 August 2019 ()
Where
2 km (1 mi) west-northwest of Humacao, PR · earthquakes near Humacao
Magnitude
M 1.8 (md)
Depth
70 km below the surface
Felt
no reports yet
Nearest
Las Piedras Municipio, 4 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2633 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, 2 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.

Earthquakes near other towns within 30 km: La Fermina, Las Piedras, Antón Ruiz, Candelero Arriba, Bajandas, Peña Pobre.

How big was it?

This earthquake released about 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× the energy of this one
  4. This earthquake M 1.8 about 17 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 14,000 times the energy of this one.

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

  1. 5.1 3 km W of Aguas Buenas, Puerto Rico · 33 km WNW of this epicentre

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 18.1543, -65.8471. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Las Piedras Municipio, PR 4 km (3 mi) NW earthquakes near Las Piedras Municipio
Humacao Municipio, PR 7 km (4 mi) ESE earthquakes near Humacao Municipio
Juncos Municipio, PR 10 km (6 mi) NW earthquakes near Juncos Municipio
Yabucoa Municipio, PR 11 km (7 mi) S earthquakes near Yabucoa Municipio
Naguabo Municipio, PR 13 km (8 mi) ENE earthquakes near Naguabo Municipio
San Lorenzo Municipio, PR 14 km (8 mi) W earthquakes near San Lorenzo 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. 1.8 18 km SW of Esperanza, Puerto Rico
  2. 2.2 4 km ESE of Bayamon, Puerto Rico
  3. 1.9 25 km SW of Esperanza, Puerto Rico
  4. 1.6 14 km WSW of Esperanza, Puerto Rico
  5. 1.8 28 km SE of Emajagua, Puerto Rico
  6. 1.8 27 km SE of Emajagua, Puerto Rico
  7. 1.6 2 km NNW of Jagual, Puerto Rico
  8. 1.8 28 km SW of Esperanza, Puerto Rico
  9. 1.6 1 km NNE of Parcelas Nuevas, Puerto Rico
  10. 1.9 26 km ESE of El Negro, Puerto Rico
  11. 1.7 25 km SE of Emajagua, Puerto Rico
  12. 2.8 24 km SW of Esperanza, Puerto Rico
  13. 1.7 26 km SE of Emajagua, Puerto Rico
  14. 1.6 18 km SE of El Negro, Puerto Rico
  15. 1.6 23 km SE 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.