Earthquake · reviewed by a seismologist
M 3.1md
108 km N of Culebra, Puerto Rico
Yes. A magnitude 3.1 earthquake was recorded 108 km N of Culebra, Puerto Rico, at 4:21 am AST on 18 September 2018 (08:21 UTC), 99 km deep.
- When
- Magnitude
- M 3.1 (md)
- Depth
- 99 km below the surface
- Felt
- no reports yet
- Nearest
- Fajardo Municipio, 107 km SSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2906 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 it was probably too small to be felt, even directly above it. 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 1,200 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 280,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 12,000× the energy of this one
- Magna, Utah 2020 M 5.7 8,800× the energy of this one
- This earthquake M 3.1 about 1,200 lb of TNT
- Around the size people start to feel M 3.0 this one released 1.3× 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 4.5 on 2018-02-09 — about 140 times the energy of this one.
Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:
- 6.1 91 km N of Charlotte Amalie, U.S. Virgin Islands · 44 km ESE of this epicentre
- 6.0 112 km N of Charlotte Amalie, U.S. Virgin Islands · 32 km ENE of this epicentre
- 5.6 112 km N of Charlotte Amalie, U.S. Virgin Islands · 37 km ENE of this epicentre
- 5.1 107 km N of Charlotte Amalie, U.S. Virgin Islands · 29 km E of this epicentre
- 5.1 122 km NNE of Vieques, Puerto Rico · 17 km NNW 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 19.2826, -65.2315. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Fajardo Municipio, PR | 107 km (66 mi) | SSW | earthquakes near Fajardo Municipio |
| Culebra Municipio, PR | 107 km (66 mi) | S | earthquakes near Culebra Municipio |
| Luquillo Municipio, PR | 113 km (71 mi) | SSW | earthquakes near Luquillo Municipio |
| Río Grande Municipio, PR | 117 km (73 mi) | SSW | earthquakes near Río Grande Municipio |
| Loíza Municipio, PR | 119 km (74 mi) | SW | earthquakes near Loíza Municipio |
| Ceiba Municipio, PR | 122 km (76 mi) | SSW | earthquakes near Ceiba Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 3.2 87 km N of Culebra, Puerto Rico
- 3.3 79 km N of Culebra, Puerto Rico
- 2.9 73 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 3.2 148 km N of Charlotte Amalie, U.S. Virgin Islands
- 4.9 143 km N of Charlotte Amalie, U.S. Virgin Islands
- 2.9 116 km NNE of Vieques, Puerto Rico
- 3.3 117 km NNE of Suárez, Puerto Rico
- 3.0 70 km N of Charlotte Amalie, U.S. Virgin Islands
- 3.1 116 km NNE of Vieques, Puerto Rico
- 2.6 83 km N of Charlotte Amalie, U.S. Virgin Islands
- 3.1 108 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 2.2 74 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 3.4 128 km NNE of Vieques, Puerto Rico
- 2.5 110 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 2.6 75 km N of Charlotte Amalie, U.S. Virgin Islands
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.