QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4ml

143 km SSW of Adak, Alaska

Yes. A magnitude 2.4 earthquake was recorded 143 km SSW of Adak, Alaska at 07:45 UTC on 2024-12-09, 25 km deep.

· 25 km deep · released about 120 lb of TNT

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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 2.4 (ml)
Depth
25 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 700 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 89,000× the energy of this one
  3. Around the size people start to feel M 3.0 7.9× the energy of this one
  4. This earthquake M 2.4 about 120 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 6.3 on 2024-12-09 — about 710,000 times the energy of this one.

Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 184 km SSW of Adak, Alaska · 44 km S of this epicentre
  2. 6.0 130 km SSW of Adak, Alaska · 13 km NNE of this epicentre
  3. 6.0 161 km SSW of Adak, Alaska · 20 km S of this epicentre
  4. 6.0 136 km S of Adak, Alaska · 41 km E of this epicentre
  5. 5.9 106 km SSW of Adak, Alaska · 38 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 50.7156, -177.5328. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.1 114 km SSW of Adak, Alaska
  2. 2.2 127 km SSW of Adak, Alaska
  3. 3.7 124 km SSW of Adak, Alaska
  4. 2.1 109 km SSW of Adak, Alaska
  5. 3.4 140 km SSW of Adak, Alaska
  6. 2.8 118 km SSW of Adak, Alaska
  7. 2.5 125 km SSW of Adak, Alaska
  8. 3.4 125 km SSW of Adak, Alaska
  9. 5.3 115 km SSW of Adak, Alaska
  10. 2.6 125 km SSW of Adak, Alaska
  11. 4.7 118 km SSW of Adak, Alaska
  12. 5.7 118 km SW of Adak, Alaska
  13. 2.8 120 km SSW of Adak, Alaska
  14. 2.4 110 km SSW of Adak, Alaska
  15. 3.3 122 km SSW of Adak, 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.