Earthquake · reviewed by a seismologist
M 3.4md
84 km N of Culebra, Puerto Rico
Yes. A magnitude 3.4 earthquake was recorded 84 km N of Culebra, Puerto Rico, at 9:48 am AST on 20 August 2018 (13:48 UTC), 56 km deep.
- When
- Magnitude
- M 3.4 (md)
- Depth
- 56 km below the surface
- Felt
- no reports yet
- Nearest
- Culebra Municipio, 83 km S
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2932 days ago
Earthquake alerts for Culebra, PR
Get a notification in this browser when USGS records an earthquake near Culebra, PR. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 8 km (5 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 1.8 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 95,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 4,300× the energy of this one
- Magna, Utah 2020 M 5.7 3,000× the energy of this one
- This earthquake M 3.4 about 1.8 tons of TNT
- Around the size people start to feel M 3.0 this one released 3.7× 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 48 times the energy of this one.
Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:
- 6.1 91 km N of Charlotte Amalie, U.S. Virgin Islands · 47 km ENE of this epicentre
- 6.0 112 km N of Charlotte Amalie, U.S. Virgin Islands · 47 km NE of this epicentre
- 5.1 107 km N of Charlotte Amalie, U.S. Virgin Islands · 43 km NE of this epicentre
- 5.1 122 km NNE of Vieques, Puerto Rico · 38 km N of this epicentre
- 5.0 109 km N of Charlotte Amalie, U.S. Virgin Islands · 39 km NE 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 19.0685, -65.2680. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Culebra Municipio, PR | 83 km (51 mi) | S | earthquakes near Culebra Municipio |
| Fajardo Municipio, PR | 83 km (52 mi) | SSW | earthquakes near Fajardo Municipio |
| Luquillo Municipio, PR | 91 km (56 mi) | SSW | earthquakes near Luquillo Municipio |
| Río Grande Municipio, PR | 95 km (59 mi) | SW | earthquakes near Río Grande Municipio |
| Ceiba Municipio, PR | 98 km (61 mi) | SSW | earthquakes near Ceiba Municipio |
| Loíza Municipio, PR | 99 km (62 mi) | SW | earthquakes near Loíza Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
48 earthquakes have been recorded within 50 km since this one.
- 2.7 52 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 2.7 59 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 2.9 55 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 3.0 60 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 3.6 62 km NNE of Culebra, Puerto Rico
- 3.1 63 km N of Culebra, Puerto Rico
- 3.0 55 km N of Culebra, Puerto Rico
- 2.8 60 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 2.2 67 km N of Culebra, Puerto Rico
- 2.6 Puerto Rico region
- 3.1 63 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 2.9 67 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 2.6 81 km N of Culebra, Puerto Rico
- 3.2 64 km NNW of Charlotte Amalie, U.S. Virgin Islands
- 3.0 Puerto Rico region
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.