QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3md

98 km N of Suárez, Puerto Rico

Yes. A magnitude 3.3 earthquake was recorded 98 km N of Suárez, Puerto Rico, at 2:14 pm AST on 21 March 2018 (18:14 UTC), 74 km deep.

· 74 km deep · released about 1.5 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Loíza Municipio 99 kmSan Juan Municipio 104 kmCarolina Municipio 105 kmCataño Municipio 105 kmRío Grande Municipio 105 kmToa Baja Municipio 105 kmFajardo Municipio 106 kmLuquillo Municipio 106 kmDorado Municipio 107 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
74 km below the surface
Felt
no reports yet
Nearest
Loíza Municipio, 99 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3068 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 it was probably too small to be felt, even directly above it. 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 1.5 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 6.7 110,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,500× the energy of this one
  4. This earthquake M 3.3 about 1.5 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 3.2× 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 4.0 on 2016-09-05 — about 9.8 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.1 122 km NNE of Vieques, Puerto Rico · 50 km ENE of this epicentre
  2. 5.1 92 km N of Suárez, Puerto Rico · 9 km SE of this epicentre
  3. 5.0 73 km NNE of Vieques, Puerto Rico · 46 km SE 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 19.3195, -65.7793. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Loíza Municipio, PR 99 km (61 mi) S earthquakes near Loíza Municipio
San Juan Municipio, PR 104 km (65 mi) SSW earthquakes near San Juan Municipio
Carolina Municipio, PR 105 km (65 mi) S earthquakes near Carolina Municipio
Cataño Municipio, PR 105 km (65 mi) SSW earthquakes near Cataño Municipio
Río Grande Municipio, PR 105 km (65 mi) S earthquakes near Río Grande Municipio
Toa Baja Municipio, PR 105 km (65 mi) SSW earthquakes near Toa Baja Municipio

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

Aftershocks so far

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

  1. 2.8 74 km N of San Juan, Puerto Rico
  2. 2.7 70 km N of San Juan, Puerto Rico
  3. 3.0 88 km NNE of Vieques, Puerto Rico
  4. 2.6 88 km NNE of Vieques, Puerto Rico
  5. 3.1 121 km NNE of Vieques, Puerto Rico
  6. 3.0 84 km NNE of Vieques, Puerto Rico
  7. 2.7 80 km NNE of Vieques, Puerto Rico
  8. 2.2 77 km NNE of Vieques, Puerto Rico
  9. 3.1 107 km NNE of Vieques, Puerto Rico
  10. 2.3 108 km N of Suárez, Puerto Rico
  11. 3.0 103 km NNE of Suárez, Puerto Rico
  12. 3.2 108 km NNE of Vieques, Puerto Rico
  13. 2.8 67 km N of San Juan, Puerto Rico
  14. 2.5 78 km N of San Juan, Puerto Rico
  15. 2.8 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.