QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5md

Mona Passage

Yes. A magnitude 3.5 earthquake was recorded in Mona Passage, 20 km (12 mi) SSW of Mayagüez, PR, at 7:41 pm AST on 13 July 2023 (23:41 UTC), 16 km deep. 20 people have reported feeling it to USGS.

20 km (12 mi) SSW of Mayagüez, PR · 128 km (79 mi) WSW of San Juan, PR

· 16 km deep · released about 3.1 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cabo Rojo Municipio 5 kmHormigueros Municipio 15 kmLajas Municipio 19 kmSan Germán Municipio 20 kmSabana Grande Municipio 28 kmAñasco Municipio 29 kmGuánica Municipio 32 kmLas Marías Municipio 33 kmMaricao Municipio 33 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 3.5 (md)
Depth
16 km below the surface
Felt
20 reports · strongest reported intensity IV
Measured shaking
intensity II (ShakeMap)
Nearest
Cabo Rojo Municipio, 5 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1152 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 64 km (40 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 5 km, intensity III · Pole Ojea 7 km, intensity III · San Germán 18 km, intensity III · Mayagüez 20 km, intensity III · Rincón 34 km, intensity II · Yauco 38 km, intensity II · Aguada 38 km, intensity II · San Sebastián 41 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 3.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 55,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,500× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,700× the energy of this one
  4. This earthquake M 3.5 about 3.1 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 6.5× more

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 19,000 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 18.0346, -67.2095. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cabo Rojo Municipio, PR 5 km (3 mi) SE earthquakes near Cabo Rojo Municipio
Hormigueros Municipio, PR 15 km (9 mi) NE earthquakes near Hormigueros Municipio
Lajas Municipio, PR 19 km (12 mi) ESE earthquakes near Lajas Municipio
San Germán Municipio, PR 20 km (12 mi) ENE earthquakes near San Germán Municipio
Sabana Grande Municipio, PR 28 km (18 mi) ENE earthquakes near Sabana Grande Municipio
Añasco Municipio, PR 29 km (18 mi) NNE earthquakes near Añasco Municipio

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

Aftershocks so far

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

  1. 2.2 4 km WSW of Palmarejo, Puerto Rico
  2. 2.3 10 km SSE of Maria Antonia, Puerto Rico
  3. 3.2 5 km SW of Guánica, Puerto Rico
  4. 2.7 9 km NW of Puerto Real, Puerto Rico
  5. 2.6 8 km WSW of La Parguera, Puerto Rico
  6. 2.6 2 km WNW of La Parguera, Puerto Rico
  7. 2.4 21 km SW of Stella, Puerto Rico
  8. 2.0 1 km E of Palomas, Puerto Rico
  9. 2.2 5 km SSE of Maria Antonia, Puerto Rico
  10. 2.1 5 km WSW of Liborio Negron Torres, Puerto Rico
  11. 2.8 Mona Passage
  12. 2.6 2 km SE of Palmarejo, Puerto Rico
  13. 2.3 10 km SSW of Guánica, Puerto Rico
  14. 2.4 4 km NNE of La Parguera, Puerto Rico
  15. 2.4 5 km SW of Fuig, 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.