Earthquake · reviewed by a seismologist
M 2.5ml
60 km S of Cordova, Alaska
Yes. A magnitude 2.5 earthquake was recorded 60 km S of Cordova, Alaska, at 10:51 am AKDT on 6 October 2021 (18:51 UTC), 21 km deep.
- When
- Magnitude
- M 2.5 (ml)
- Depth
- 21 km below the surface
- Felt
- no reports yet
- Nearest
- Chugach Census Area, 60 km NNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1799 days ago
Earthquake alerts for Cordova, AK
Get a notification in this browser when USGS records an earthquake near Cordova, AK. 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 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
- Magna, Utah 2020 M 5.7 63,000× the energy of this one
- Around the size people start to feel M 3.0 5.6× the energy of this one
- This earthquake M 2.5 about 170 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
The largest earthquake within 50 km since 2016 was M 4.9 on 2021-01-25 — about 4,000 times the energy of this one.
Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:
- 6.0 78 km S of Cordova, Alaska · 18 km SSW of this epicentre
- 5.7 65 km SSW of Cordova, Alaska · 37 km W of this epicentre
- 5.7 30 km SSW of Cordova, Alaska · 39 km NNW of this epicentre
- 5.7 27 km SSW of Cordova, Alaska · 40 km NNW of this epicentre
- 5.6 25 km SW of Cordova, Alaska · 43 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 60.0014, -145.7263. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Chugach Census Area, AK | 60 km (37 mi) | NNW | earthquakes near Chugach Census Area |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
60 earthquakes have been recorded within 50 km since this one.
- 1.9 39 km SSW of Cordova, Alaska
- 1.5 43 km S of Cordova, Alaska
- 1.5 64 km SSW of Cordova, Alaska
- 1.7 38 km S of Cordova, Alaska
- 1.7 33 km SW of Cordova, Alaska
- 1.9 34 km SE of Cordova, Alaska
- 2.5 65 km SSW of Cordova, Alaska
- 2.3 81 km S of Cordova, Alaska
- 1.8 44 km SE of Cordova, Alaska
- 2.3 81 km SSW of Cordova, Alaska
- 1.9 60 km SSE of Cordova, Alaska
- 2.1 46 km SSE of Cordova, Alaska
- 1.7 30 km SE of Cordova, Alaska
- 2.2 47 km SSE of Cordova, Alaska
- 1.6 11 km SSE of Cordova, Alaska
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.