QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Mona Passage

Yes. A magnitude 2.8 earthquake was recorded in Mona Passage, 14 km (9 mi) SSW of Mayagüez, PR, at 8:29 pm AST on 21 July 2023 (00:29 UTC), 17 km deep.

14 km (9 mi) SSW of Mayagüez, PR · 124 km (77 mi) WSW of San Juan, PR

· 17 km deep · released about 480 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Hormigueros Municipio 10 kmCabo Rojo Municipio 10 kmSan Germán Municipio 16 kmLajas Municipio 20 kmAñasco Municipio 23 kmSabana Grande Municipio 26 kmLas Marías Municipio 28 kmMaricao Municipio 29 kmRincón Municipio 29 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
Magnitude
M 2.8 (md)
Depth
17 km below the surface
Felt
no reports yet
Nearest
Hormigueros Municipio, 10 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1209 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 21 km (13 mi) from the epicentre. 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.

Likely felt in: Puerto Real in town, intensity II · Pole Ojea 12 km, intensity II · Mayagüez 14 km, intensity II · San Germán 16 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 6.4 on 2020-01-07 — about 250,000 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 18.0867, -67.1915. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Hormigueros Municipio, PR 10 km (6 mi) NE earthquakes near Hormigueros Municipio
Cabo Rojo Municipio, PR 10 km (6 mi) S earthquakes near Cabo Rojo Municipio
San Germán Municipio, PR 16 km (10 mi) E earthquakes near San Germán Municipio
Lajas Municipio, PR 20 km (12 mi) SE earthquakes near Lajas Municipio
Añasco Municipio, PR 23 km (14 mi) NNE earthquakes near Añasco Municipio
Sabana Grande Municipio, PR 26 km (16 mi) E earthquakes near Sabana Grande Municipio

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

Aftershocks so far

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

  1. 2.6 2 km SSW of Guánica, Puerto Rico
  2. 3.0 5 km SSE of Pole Ojea, Puerto Rico
  3. 2.1 7 km WSW of Guánica, Puerto Rico
  4. 2.5 Puerto Rico region
  5. 2.0 7 km SSE of Guánica, Puerto Rico
  6. 2.5 Puerto Rico region
  7. 2.8 17 km WNW of Rincón, Puerto Rico
  8. 1.8 7 km ESE of Pole Ojea, Puerto Rico
  9. 2.5 6 km E of Espino, Puerto Rico
  10. 2.4 8 km WSW of La Parguera, Puerto Rico
  11. 3.0 Puerto Rico region
  12. 2.2 3 km SSW of Indios, Puerto Rico
  13. 2.2 4 km NE of La Parguera, Puerto Rico
  14. 2.3 2 km NNW of Indios, Puerto Rico
  15. 2.8 5 km SW of Liborio Negron Torres, 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.