Earthquake · reviewed by a seismologist
M 3.3md
55 km WSW of Stella, Puerto Rico
Yes. A magnitude 3.3 earthquake was recorded 55 km WSW of Stella, Puerto Rico, at 3:22 am AST on 21 November 2020 (07:22 UTC), 40 km deep. 1 person has reported feeling it to USGS.
- When
- Magnitude
- M 3.3 (md)
- Depth
- 40 km below the surface
- Felt
- 1 report · strongest reported intensity IV
- Nearest
- Mayagüez Municipio, 18 km W
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2107 days ago
Earthquake alerts for Stella, PR
Get a notification in this browser when USGS records an earthquake near Stella, 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 30 km (19 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 1.2 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 140,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 6,500× the energy of this one
- Magna, Utah 2020 M 5.7 4,600× the energy of this one
- This earthquake M 3.3 about 1.2 tons of TNT
- Around the size people start to feel M 3.0 this one released 2.5× 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 2017-10-01 — about 51 times the energy of this one.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 6.3 58 km E of Punta Cana, Dominican Republic · 46 km NNW of this epicentre
- 5.2 19 km SW of Stella, Puerto Rico · 38 km ENE of this epicentre
- 5.1 21 km SW of Stella, Puerto Rico · 38 km E 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 18.1081, -67.7220. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mayagüez Municipio, PR | 18 km (11 mi) | W | earthquakes near Mayagüez Municipio |
| Rincón Municipio, PR | 56 km (35 mi) | ENE | earthquakes near Rincón Municipio |
| Cabo Rojo Municipio, PR | 59 km (36 mi) | ESE | earthquakes near Cabo Rojo Municipio |
| Aguada Municipio, PR | 64 km (40 mi) | ENE | earthquakes near Aguada Municipio |
| Hormigueros Municipio, PR | 64 km (40 mi) | E | earthquakes near Hormigueros Municipio |
| Añasco Municipio, PR | 65 km (41 mi) | ENE | earthquakes near Añasco Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
37 earthquakes have been recorded within 50 km since this one.
- 2.5 22 km W of Pole Ojea, Puerto Rico
- 2.2 29 km W of Stella, Puerto Rico
- 2.5 18 km WNW of Puerto Real, Puerto Rico
- 3.0 54 km W of Rincón, Puerto Rico
- 3.9 40 km WNW of Rincón, Puerto Rico
- 2.9 24 km W of Puerto Real, Puerto Rico
- 2.7 36 km WSW of Stella, Puerto Rico
- 3.5 53 km SE of Punta Cana, Dominican Republic
- 3.7 66 km SE of Boca de Yuma, Dominican Republic
- 2.5 23 km W of Puerto Real, Puerto Rico
- 1.9 17 km WSW of Pole Ojea, Puerto Rico
- 2.2 30 km W of Pole Ojea, Puerto Rico
- 2.2 27 km W of Pole Ojea, Puerto Rico
- 2.2 14 km NW of Puerto Real, Puerto Rico
- 2.2 18 km SW of Stella, 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.