Earthquake · reviewed by a seismologist
M 3.3md
South Carolina
Yes. A magnitude 3.3 earthquake was recorded South Carolina, 9 km (5 mi) WNW of North Charleston, SC, at 6:21 pm EDT on 27 September 2021 (22:21 UTC), 6.8 km deep. 2,806 people have reported feeling it to USGS.
9 km (5 mi) WNW of North Charleston, SC · 7 km (5 mi) SSE of Summerville, SC
- When
- South Carolina today
- every earthquake in South Carolina in the last 24 hours
- Magnitude
- M 3.3 (md)
- Depth
- 6.8 km below the surface
- Felt
- 2,806 reports · strongest reported intensity V
- Measured shaking
- intensity IV (ShakeMap)
- Nearest
- Charleston County, 25 km SE
- Nearest mapped fault
- Charleston liquefaction features, under 1 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1788 days ago
Earthquake alerts for Ladson, SC
Get a notification in this browser when USGS records an earthquake near Ladson, SC. 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 221 km (137 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.
Earthquakes near other towns within 30 km: Ladson, Lincolnville, Summerville, Sangaree, Goose Creek, Hanahan.
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 6,200× the energy of this one
- Magna, Utah 2020 M 5.7 4,400× 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.
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 32.9440, -80.1540. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Charleston County, SC | 25 km (16 mi) | SE | earthquakes near Charleston County |
| Dorchester County, SC | 28 km (17 mi) | WNW | earthquakes near Dorchester County |
| Berkeley County, SC | 35 km (22 mi) | NNE | earthquakes near Berkeley County |
| Colleton County, SC | 48 km (30 mi) | WSW | earthquakes near Colleton County |
| Clarendon County, SC | 80 km (50 mi) | N | earthquakes near Clarendon County |
| Orangeburg County, SC | 81 km (51 mi) | NW | earthquakes near Orangeburg County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
15 earthquakes have been recorded within 50 km since this one.
- 1.8 6 km SSW of Ladson, South Carolina
- 2.5 6 km SSW of Ladson, South Carolina
- 1.6 6 km SSE of Centerville, South Carolina
- 1.6 6 km SW of Ladson, South Carolina
- 2.9 6 km SW of Ladson, South Carolina
- 2.2 3 km SSW of Centerville, South Carolina
- 1.9 6 km SSW of Ladson, South Carolina
- 1.8 11 km SSW of Centerville, South Carolina
- 2.2 1 km NE of Summerville, South Carolina
- 2.1 11 km SW of Centerville, South Carolina
- 1.6 3 km NNW of Summerville, South Carolina
- 1.7 1 km SSW of Sangaree, South Carolina
- 2.4 6 km SSW of Ladson, South Carolina
- 1.6 5 km SSE of Centerville, South Carolina
- 1.5 3 km S of Centerville, South Carolina
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.