QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

Earthquake near King Cove, AK

No earthquake was likely felt in King Cove in the 24 hours to 2:13 pm AKST (23:13 UTC). The last one was M 5.0, 171 km (106 mi) SSW, at 12:14 pm AKDT on 29 October 2026, estimated intensity II (weak) in town. Every earthquake near King Cove

This page: a magnitude 2.7 earthquake was recorded 34 km (21 mi) west of King Cove, AK, at 3:43 am AKDT on 20 March 2021 (11:43 UTC), 103 km deep.

USGS: 16 km SSW of Cold Bay, Alaska

3:43 am AKDT, Mar 20, 2021 · · 103 km deep · released about 340 lb of TNT

Every earthquake near King Cove Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aleutians East Borough 58 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
3:43 am AKDT on 20 March 2021 ()
Where
34 km (21 mi) west of King Cove, AK · earthquakes near King Cove
Magnitude
M 2.7 (ml)
Depth
103 km below the surface
Felt
no reports yet
Nearest
Aleutians East Borough, 58 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1990 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In King Cove, 34 km away, the estimate is intensity I (not felt). 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 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.8× the energy of this one
  4. This earthquake M 2.7 about 340 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 4.6 on 2018-07-02 — about 710 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.9 14 km NNE of False Pass, Alaska · 32 km WSW 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 55.0605, -162.8491. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aleutians East Borough, AK 58 km (36 mi) ENE earthquakes near Aleutians East Borough

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

25 earthquakes have been recorded within 50 km since this one.

  1. 3.1 30 km NNW of Cold Bay, Alaska
  2. 3.0 21 km SE of False Pass, Alaska
  3. 2.6 29 km SE of False Pass, Alaska
  4. 3.0 34 km N of Cold Bay, Alaska
  5. 1.9 31 km S of Cold Bay, Alaska
  6. 2.2 12 km WNW of Cold Bay, Alaska
  7. 2.0 43 km ESE of False Pass, Alaska
  8. 2.7 25 km ENE of Cold Bay, Alaska
  9. 3.1 32 km NNE of Cold Bay, Alaska
  10. 2.1 46 km ESE of False Pass, Alaska
  11. 2.2 20 km S of King Cove, Alaska
  12. 1.8 14 km NNE of False Pass, Alaska
  13. 1.8 13 km WSW of King Cove, Alaska
  14. 1.9 26 km ENE of False Pass, Alaska
  15. 1.7 50 km ESE of False Pass, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.