QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

150 km SSW of Akhiok, Alaska

Yes. A magnitude 2.8 earthquake was recorded 150 km SSW of Akhiok, Alaska at 21:34 UTC on 2024-12-05, 12 km deep.

· 12 km deep · released about 480 lb of TNT

10 km30 km60 km120 km N
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
Magnitude
M 2.8 (ml)
Depth
12 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 636 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, people at rest would likely notice it out to about 24 km (15 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 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 4.8 on 2021-07-29 — about 1,000 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 171 km SW of Akhiok, Alaska · 34 km W of this epicentre
  2. 6.2 108 km SSW of Akhiok, Alaska · 46 km NE of this epicentre
  3. 6.2 148 km SSW of Akhiok, Alaska · 6 km E of this epicentre
  4. 6.0 108 km SSW of Akhiok, Alaska · 42 km NNE of this epicentre
  5. 5.9 124 km SSW of Akhiok, Alaska · 28 km NE 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 55.7472, -155.3013. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.7 183 km SSW of Akhiok, Alaska
  2. 3.0 183 km SSW of Akhiok, Alaska
  3. 2.6 156 km SSW of Akhiok, Alaska
  4. 2.9 155 km SSW of Akhiok, Alaska
  5. 2.4 156 km SSW of Akhiok, Alaska
  6. 3.1 150 km SW of Akhiok, Alaska
  7. 2.3 172 km SSW of Akhiok, Alaska
  8. 2.8 179 km SSW of Akhiok, Alaska
  9. 2.7 149 km SSW of Akhiok, Alaska
  10. 1.8 159 km SSW of Akhiok, Alaska
  11. 1.8 172 km SW of Akhiok, Alaska
  12. 2.7 147 km SSW of Akhiok, Alaska
  13. 2.3 113 km SSW of Akhiok, Alaska
  14. 2.9 149 km SW of Akhiok, Alaska
  15. 2.7 126 km SW of Akhiok, 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.