QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5md

77 km NW of San Antonio, Puerto Rico

Yes. A magnitude 3.5 earthquake was recorded 77 km NW of San Antonio, Puerto Rico, at 6:22 am AST on 8 May 2020 (10:22 UTC), 5.0 km deep. 1 person has reported feeling it to USGS.

· 5.0 km deep · released about 3 tons of TNT

10 km30 km60 km120 km N Aguadilla Municipio 75 kmRincón Municipio 82 kmAguada Municipio 82 kmIsabela Municipio 85 kmMoca Municipio 89 kmQuebradillas Municipio 93 kmAñasco Municipio 93 kmCamuy Municipio 100 kmSan Sebastián Municipio 100 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
5.0 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Aguadilla Municipio, 75 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2296 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 65 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.

How big was it?

This earthquake released about 3 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 57,000× 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 1,800× the energy of this one
  4. This earthquake M 3.5 about 3 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 6.2× 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 6.0 on 2019-09-24 — about 5,100 times the energy of this one.

Before 2016, the USGS record lists 17 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 94 km NE of Punta Cana, Dominican Republic · 19 km NNW of this epicentre
  2. 6.4 32 km NW of Aguadilla, Puerto Rico · 48 km SSE of this epicentre
  3. 6.1 80 km NE of Punta Cana, Dominican Republic · 33 km WNW of this epicentre
  4. 6.0 67 km NNW of San Antonio, Puerto Rico · 40 km ENE of this epicentre
  5. 5.8 33 km NW of San Antonio, Puerto Rico · 44 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 18.9868, -67.6210. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguadilla Municipio, PR 75 km (47 mi) SE earthquakes near Aguadilla Municipio
Rincón Municipio, PR 82 km (51 mi) SSE earthquakes near Rincón Municipio
Aguada Municipio, PR 82 km (51 mi) SE earthquakes near Aguada Municipio
Isabela Municipio, PR 85 km (53 mi) SE earthquakes near Isabela Municipio
Moca Municipio, PR 89 km (55 mi) SE earthquakes near Moca Municipio
Quebradillas Municipio, PR 93 km (58 mi) SE earthquakes near Quebradillas Municipio

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

Aftershocks so far

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

  1. 2.6 85 km NW of San Antonio, Puerto Rico
  2. 3.3 85 km NW of San Antonio, Puerto Rico
  3. 3.6 81 km NE of Punta Cana, Dominican Republic
  4. 3.3 76 km NW of San Antonio, Puerto Rico
  5. 3.0 81 km NE of Punta Cana, Dominican Republic
  6. 2.7 87 km NW of San Antonio, Puerto Rico
  7. 3.4 84 km NNW of San Antonio, Puerto Rico
  8. 3.4 101 km NW of San Antonio, Puerto Rico
  9. 2.9 92 km NE of Punta Cana, Dominican Republic
  10. 3.6 89 km NE of Punta Cana, Dominican Republic
  11. 3.5 77 km NW of San Antonio, Puerto Rico
  12. 2.7 92 km NW of San Antonio, Puerto Rico
  13. 3.7 84 km NW of San Antonio, Puerto Rico
  14. 3.4 86 km NW of San Antonio, Puerto Rico
  15. 3.8 Mona Passage

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.