QuakeIndex

Earthquake · reviewed by a seismologist

M 3.7md

Earthquake near Punta Santiago, PR

No earthquake was likely felt in Punta Santiago in the 24 hours to 9:03 am AST (13:03 UTC). The last one was M 4.1, 49 km (31 mi) ESE, at 5:44 am AST on 28 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near Punta Santiago

This page: a magnitude 3.7 earthquake was recorded 5 km (3 mi) east of Punta Santiago, PR, at 3:49 am AST on 21 August 2022 (07:49 UTC), 14 km deep. 3 people have reported feeling it to USGS.

USGS: 4 km E of Punta Santiago, Puerto Rico

47 km (29 mi) SE of San Juan, PR · 36 km (23 mi) ESE of Caguas, PR

3:49 am AST, Aug 21, 2022 · · 14 km deep · released about 5.5 tons of TNT

Every earthquake near Punta Santiago Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Naguabo Municipio 6 kmHumacao Municipio 10 kmCeiba Municipio 13 kmLas Piedras Municipio 18 kmYabucoa Municipio 20 kmLuquillo Municipio 23 kmJuncos Municipio 23 kmRío Grande Municipio 26 kmCanóvanas Municipio 27 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
3:49 am AST on 21 August 2022 ()
Where
5 km (3 mi) east of Punta Santiago, PR · earthquakes near Punta Santiago
Magnitude
M 3.7 (md)
Depth
14 km below the surface
Felt
3 reports · strongest reported intensity II
Nearest
Naguabo Municipio, 6 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1471 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 75 km (47 mi) from the epicentre. In Punta Santiago, 5 km away, the estimate is intensity III (weak). 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: Aguas Claras 11 km, intensity III · Humacao 13 km, intensity III · Fajardo 19 km, intensity III · Luquillo 23 km, intensity III · Esperanza 26 km, intensity III · Emajagua 27 km, intensity III · Isabel Segunda 27 km, intensity III · Río Grande 28 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 5.5 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 31,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 970× the energy of this one
  4. This earthquake M 3.7 about 5.5 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 12× 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 2021-10-08 — about 43 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.1 3 km W of Aguas Buenas, Puerto Rico · 47 km WNW 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 18.1656, -65.7015. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Naguabo Municipio, PR 6 km (4 mi) NW earthquakes near Naguabo Municipio
Humacao Municipio, PR 10 km (6 mi) WSW earthquakes near Humacao Municipio
Ceiba Municipio, PR 13 km (8 mi) NE earthquakes near Ceiba Municipio
Las Piedras Municipio, PR 18 km (11 mi) W earthquakes near Las Piedras Municipio
Yabucoa Municipio, PR 20 km (13 mi) SW earthquakes near Yabucoa Municipio
Luquillo Municipio, PR 23 km (14 mi) N earthquakes near Luquillo Municipio

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

Aftershocks so far

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

  1. 2.3 Puerto Rico region
  2. 1.9 9 km SSW of Emajagua, Puerto Rico
  3. 3.1 Puerto Rico region
  4. 3.3 16 km NW of Culebra, Puerto Rico
  5. 3.3 15 km S of Esperanza, Puerto Rico
  6. 2.8 16 km S of Lamboglia, Puerto Rico
  7. 2.5 12 km SE of Esperanza, Puerto Rico
  8. 2.8 Puerto Rico region
  9. 2.9 Puerto Rico region
  10. 2.4 5 km ESE of Punta Santiago, Puerto Rico
  11. 2.8 28 km SE of Emajagua, Puerto Rico
  12. 3.2 24 km SW of Esperanza, Puerto Rico
  13. 3.3 3 km SE of Trujillo Alto, Puerto Rico
  14. 2.5 6 km S of Esperanza, Puerto Rico
  15. 3.4 25 km NNE of Playa Fortuna, 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.