Earthquake · reviewed by a seismologist
M 3.9md
118 km N of Brenas, Puerto Rico
Yes. A magnitude 3.9 earthquake was recorded 118 km N of Brenas, Puerto Rico, at 1:24 am AST on 27 May 2023 (05:24 UTC), 28 km deep.
- When
- Magnitude
- M 3.9 (md)
- Depth
- 28 km below the surface
- Felt
- no reports yet
- Nearest
- Dorado Municipio, 118 km S
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1201 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 84 km (52 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 10 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 16,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 730× the energy of this one
- Magna, Utah 2020 M 5.7 520× the energy of this one
- This earthquake M 3.9 about 10 tons of TNT
- Around the size people start to feel M 3.0 this one released 22× 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 4.4 on 2016-10-23 — about 5.8 times the energy of this one.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 5.7 78 km N of Tierras Nuevas Poniente, Puerto Rico · 50 km SW of this epicentre
- 5.4 106 km N of Brenas, Puerto Rico · 15 km SW of this epicentre
- 5.0 113 km N of Brenas, Puerto Rico · 6 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 19.5360, -66.2878. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Dorado Municipio, PR | 118 km (73 mi) | S | earthquakes near Dorado Municipio |
| Barceloneta Municipio, PR | 122 km (76 mi) | SSW | earthquakes near Barceloneta Municipio |
| Quebradillas Municipio, PR | 137 km (85 mi) | SSW | earthquakes near Quebradillas Municipio |
| Isabela Municipio, PR | 140 km (87 mi) | SSW | earthquakes near Isabela Municipio |
| Aguadilla Municipio, PR | 148 km (92 mi) | SW | earthquakes near Aguadilla Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
30 earthquakes have been recorded within 50 km since this one.
- 3.2 89 km N of Brenas, Puerto Rico
- 3.9 98 km N of Brenas, Puerto Rico
- 3.9 111 km N of Brenas, Puerto Rico
- 3.4 104 km NNE of San Juan, Puerto Rico
- 3.5 124 km N of San Juan, Puerto Rico
- 3.1 Puerto Rico region
- 3.1 Puerto Rico region
- 4.0 111 km N of San Juan, Puerto Rico
- 3.8 115 km N of San Juan, Puerto Rico
- 3.7 120 km N of San Juan, Puerto Rico
- 3.8 127 km N of San Juan, Puerto Rico
- 3.4 104 km N of San Juan, Puerto Rico
- 3.9 144 km N of San Juan, Puerto Rico
- 3.4 125 km N of San Juan, Puerto Rico
- 3.8 158 km N of San Juan, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.