Earthquake · reviewed by a seismologist
M 2.3md
Earthquake near Alcoa, TN
No earthquake was likely felt in Alcoa in the 24 hours to 9:13 am EST (14:13 UTC). The last one was M 2.1, 12 km (8 mi) NNE, at 2:55 pm EST on 5 November 2026, estimated intensity II (weak) in town. Every earthquake near Alcoa
This page: a magnitude 2.3 earthquake was recorded 3 km (2 mi) southwest of Alcoa, TN, at 4:21 pm EDT on 11 July 2021 (20:21 UTC), 22 km deep.
USGS: 3 km SW of Alcoa, Tennessee
23 km (14 mi) SSW of Knoxville, TN
- When
- 4:21 pm EDT on 11 July 2021 ()
- Where
- 3 km (2 mi) southwest of Alcoa, TN · earthquakes near Alcoa
- Magnitude
- M 2.3 (md)
- Depth
- 22 km below the surface
- Felt
- no reports yet
- Nearest
- Blount County, 12 km SE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1948 days ago
Earthquake alerts for Alcoa, TN
Get a notification in this browser when USGS records an earthquake near Alcoa, TN. 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 minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 29 km (18 mi) from the epicentre. In Alcoa, 3 km away, the estimate is intensity II (weak). 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.
Likely felt in: Maryville 3 km, intensity II · Farragut 18 km, intensity II · Knoxville 22 km, intensity II · Seymour 29 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 79 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 190,000× the energy of this one
- Magna, Utah 2020 M 5.7 130,000× the energy of this one
- Around the size people start to feel M 3.0 12× the energy of this one
- This earthquake M 2.3 about 79 lb of TNT
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 35.7710, -84.0045. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Blount County, TN | 12 km (7 mi) | SE | earthquakes near Blount County |
| Knox County, TN | 25 km (16 mi) | NNE | earthquakes near Knox County |
| Loudon County, TN | 28 km (18 mi) | W | earthquakes near Loudon County |
| Anderson County, TN | 42 km (26 mi) | NNW | earthquakes near Anderson County |
| Monroe County, TN | 42 km (26 mi) | SSW | earthquakes near Monroe County |
| Sevier County, TN | 43 km (27 mi) | E | earthquakes near Sevier County |
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.
- 2.1 Tennessee
- 2.2 1 km S of Garland, Tennessee
- 2.7 3 km S of Blaine, Tennessee
- 2.0 3 km ESE of Vonore, Tennessee
- 1.8 4 km SSW of Loudon, Tennessee
- 2.0 3 km SSW of Maryville, Tennessee
- 2.0 Tennessee
- 2.1 5 km S of Greenback, Tennessee
- 1.8 6 km NNW of Farragut, Tennessee
- 2.5 Tennessee
- 1.7 3 km NE of Greenback, Tennessee
- 1.8 Tennessee
- 1.8 4 km NE of Vonore, Tennessee
- 2.2 4 km ENE of Madisonville, Tennessee
- 1.8 4 km SW of Sweetwater, Tennessee
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.