QuakeIndex

Earthquake · reviewed by a seismologist

M 4.3md

109 km N of San Antonio, Puerto Rico

Yes. A magnitude 4.3 earthquake was recorded 109 km N of San Antonio, Puerto Rico, at 10:01 pm AST on 7 August 2023 (02:01 UTC), 21 km deep. 4 people have reported feeling it to USGS.

· 21 km deep · released about 44 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aguadilla Municipio 111 kmIsabela Municipio 113 kmQuebradillas Municipio 116 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 4.3 (md)
Depth
21 km below the surface
Felt
4 reports · strongest reported intensity II
Nearest
Aguadilla Municipio, 111 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1121 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 120 km (75 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.

How big was it?

This earthquake released about 44 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 3,800× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 170× the energy of this one
  3. Magna, Utah 2020 M 5.7 120× the energy of this one
  4. This earthquake M 4.3 about 44 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 92× 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 since 2016 was M 6.0 on 2019-09-24 — about 340 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.0 93 km NNW of San Antonio, Puerto Rico · 20 km SSW of this epicentre
  2. 6.0 81 km N of Isabela, Puerto Rico · 40 km SE of this epicentre
  3. 6.0 67 km NNW of San Antonio, Puerto Rico · 45 km S of this epicentre
  4. 5.7 88 km N of San Antonio, Puerto Rico · 23 km SSW of this epicentre
  5. 5.5 65 km N of Isabela, Puerto Rico · 45 km SSE 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 19.4800, -67.2030. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguadilla Municipio, PR 111 km (69 mi) S earthquakes near Aguadilla Municipio
Isabela Municipio, PR 113 km (70 mi) S earthquakes near Isabela Municipio
Quebradillas Municipio, PR 116 km (72 mi) SSE earthquakes near Quebradillas Municipio
Camuy Municipio, PR 120 km (75 mi) SSE earthquakes near Camuy Municipio
Hatillo Municipio, PR 123 km (76 mi) SSE earthquakes near Hatillo Municipio
Arecibo Municipio, PR 129 km (80 mi) SSE earthquakes near Arecibo Municipio

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

Aftershocks so far

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

  1. 3.7 85 km NNW of San Antonio, Puerto Rico
  2. 3.4 75 km N of Isabela, Puerto Rico
  3. 3.6 100 km NNW of San Antonio, Puerto Rico
  4. 3.3 103 km NNW of San Antonio, Puerto Rico
  5. 3.3 77 km N of San Antonio, Puerto Rico
  6. 3.5 135 km NNW of San Antonio, Puerto Rico
  7. 3.2 71 km N of Isabela, Puerto Rico
  8. 3.3 60 km N of Isabela, Puerto Rico
  9. 3.4 71 km NNW of San Antonio, Puerto Rico
  10. 3.7 64 km N of Isabela, Puerto Rico
  11. 3.2 97 km NNW of San Antonio, Puerto Rico
  12. 3.7 107 km NNW of San Antonio, Puerto Rico
  13. 3.9 93 km NNW of San Antonio, Puerto Rico
  14. 3.3 101 km NNW of San Antonio, Puerto Rico
  15. 3.2 90 km NNW of San Antonio, 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.