Earthquake · reviewed by a seismologist
M 4.0md
109 km N of Suárez, Puerto Rico
Yes. A magnitude 4.0 earthquake was recorded 109 km N of Suárez, Puerto Rico, at 2:08 pm AST on 21 May 2023 (18:08 UTC), 77 km deep. 1 person has reported feeling it to USGS.
- When
- Magnitude
- M 4.0 (md)
- Depth
- 77 km below the surface
- Felt
- 1 report · strongest reported intensity II
- Nearest
- Loíza Municipio, 109 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 55 km (34 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 14 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 12,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 560× the energy of this one
- Magna, Utah 2020 M 5.7 390× the energy of this one
- This earthquake M 4.0 about 14 tons of TNT
- Around the size people start to feel M 3.0 this one released 29× 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 2023-02-28 — about 5.1 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.1 122 km NNE of Vieques, Puerto Rico · 49 km E of this epicentre
- 5.1 92 km N of Suárez, Puerto Rico · 18 km SSE 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 19.4156, -65.7795. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Loíza Municipio, PR | 109 km (68 mi) | S | earthquakes near Loíza Municipio |
| San Juan Municipio, PR | 115 km (71 mi) | SSW | earthquakes near San Juan Municipio |
| Cataño Municipio, PR | 115 km (71 mi) | SSW | earthquakes near Cataño Municipio |
| Carolina Municipio, PR | 115 km (71 mi) | S | earthquakes near Carolina Municipio |
| Toa Baja Municipio, PR | 115 km (72 mi) | SSW | earthquakes near Toa Baja Municipio |
| Río Grande Municipio, PR | 116 km (72 mi) | S | earthquakes near Río Grande 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.
- 3.8 142 km N of Suárez, Puerto Rico
- 3.8 Puerto Rico region
- 4.0 132 km N of Suárez, Puerto Rico
- 3.9 135 km N of Suárez, Puerto Rico
- 3.5 90 km N of Suárez, Puerto Rico
- 3.7 129 km N of Suárez, Puerto Rico
- 3.8 122 km N of Suárez, Puerto Rico
- 3.5 122 km N of Suárez, Puerto Rico
- 3.9 110 km N of Suárez, Puerto Rico
- 3.8 149 km N of Suárez, Puerto Rico
- 3.7 135 km N of Suárez, Puerto Rico
- 3.4 106 km NNE of Suárez, Puerto Rico
- 3.7 149 km N of Suárez, Puerto Rico
- 3.8 135 km N of Suárez, Puerto Rico
- 3.8 135 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.