Earthquake · reviewed by a seismologist
M 3.9md
107 km NNE of San Juan, Puerto Rico
Yes. A magnitude 3.9 earthquake was recorded 107 km NNE of San Juan, Puerto Rico, at 4:22 am AST on 25 January 2023 (08:22 UTC), 27 km deep.
- When
- Magnitude
- M 3.9 (md)
- Depth
- 27 km below the surface
- Felt
- no reports yet
- Nearest
- Loíza Municipio, 107 km S
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1310 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 85 km (53 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 11 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 5.8 710× the energy of this one
- Magna, Utah 2020 M 5.7 500× the energy of this one
- This earthquake M 3.9 about 11 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 4.3 on 2022-12-25 — about 4.7 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.1 92 km N of Suárez, Puerto Rico · 20 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 19.4056, -65.8381. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Loíza Municipio, PR | 107 km (67 mi) | S | earthquakes near Loíza Municipio |
| Cataño Municipio, PR | 112 km (69 mi) | SSW | earthquakes near Cataño Municipio |
| Toa Baja Municipio, PR | 112 km (70 mi) | SSW | earthquakes near Toa Baja Municipio |
| San Juan Municipio, PR | 112 km (70 mi) | SSW | earthquakes near San Juan Municipio |
| Dorado Municipio, PR | 113 km (70 mi) | SSW | earthquakes near Dorado Municipio |
| Carolina Municipio, PR | 113 km (70 mi) | S | earthquakes near Carolina Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
40 earthquakes have been recorded within 50 km since this one.
- 3.8 146 km N of Suárez, Puerto Rico
- 3.4 144 km N of Suárez, Puerto Rico
- 3.8 134 km N of Su?rez, Puerto Rico
- 3.4 119 km N of Suárez, Puerto Rico
- 3.8 121 km N of Suárez, Puerto Rico
- 3.3 153 km N of Suárez, Puerto Rico
- 3.9 Puerto Rico region
- 3.4 69 km NNE of Suárez, Puerto Rico
- 3.7 139 km N of Suárez, Puerto Rico
- 4.1 139 km N of Suárez, Puerto Rico
- 4.1 132 km N of Suárez, Puerto Rico
- 4.0 109 km N of Suárez, Puerto Rico
- 4.0 Puerto Rico region
- 4.1 141 km N of Suárez, Puerto Rico
- 4.0 128 km N of Suárez, 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.