QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3md

82 km N of San Juan, Puerto Rico

Yes. A magnitude 3.3 earthquake was recorded 82 km N of San Juan, Puerto Rico, 90 km (56 mi) N of San Juan, PR, at 3:47 am AST on 28 March 2023 (07:47 UTC), 22 km deep. 1 person has reported feeling it to USGS.

90 km (56 mi) N of San Juan, PR

· 22 km deep · released about 1.1 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Dorado Municipio 81 kmToa Baja Municipio 83 kmCataño Municipio 85 kmVega Baja Municipio 85 kmVega Alta Municipio 86 kmSan Juan Municipio 88 kmBarceloneta Municipio 89 kmLoíza Municipio 89 kmManatí Municipio 89 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 3.3 (md)
Depth
22 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Dorado Municipio, 81 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1324 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 44 km (27 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 1.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 150,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 6,700× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,700× the energy of this one
  4. This earthquake M 3.3 about 1.1 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.4× 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 4.8 on 2017-08-18 — about 210 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.9 78 km N of Arecibo, Puerto Rico · 45 km W of this epicentre
  2. 5.7 78 km N of Tierras Nuevas Poniente, Puerto Rico · 36 km W of this epicentre
  3. 5.5 64 km N of Tierras Nuevas Poniente, Puerto Rico · 33 km WSW of this epicentre
  4. 5.4 106 km N of Brenas, Puerto Rico · 31 km NW of this epicentre
  5. 5.1 66 km N of Brenas, Puerto Rico · 22 km SW 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 19.2040, -66.2185. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Dorado Municipio, PR 81 km (50 mi) S earthquakes near Dorado Municipio
Toa Baja Municipio, PR 83 km (52 mi) S earthquakes near Toa Baja Municipio
Cataño Municipio, PR 85 km (53 mi) S earthquakes near Cataño Municipio
Vega Baja Municipio, PR 85 km (53 mi) SSW earthquakes near Vega Baja Municipio
Vega Alta Municipio, PR 86 km (54 mi) S earthquakes near Vega Alta Municipio
San Juan Municipio, PR 88 km (55 mi) S earthquakes near San Juan Municipio

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

Aftershocks so far

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

  1. 3.5 Puerto Rico region
  2. 3.4 Puerto Rico region
  3. 3.1 51 km N of San Juan, Puerto Rico
  4. 3.4 81 km N of Arecibo, Puerto Rico
  5. 3.4 59 km N of Tierras Nuevas Poniente, Puerto Rico
  6. 3.4 66 km N of Tierras Nuevas Poniente, Puerto Rico
  7. 3.9 118 km N of Brenas, Puerto Rico
  8. 3.7 127 km N of Brenas, Puerto Rico
  9. 3.2 63 km NNE of San Juan, Puerto Rico
  10. 3.4 70 km NNE of Arecibo, Puerto Rico
  11. 3.4 Puerto Rico region
  12. 3.3 49 km N of San Juan, Puerto Rico
  13. 3.2 78 km N of San Juan, Puerto Rico
  14. 3.3 Puerto Rico region
  15. 3.0 Puerto Rico region

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.