QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

207 km W of Adak, Alaska

Yes. A magnitude 2.8 earthquake was recorded 207 km W of Adak, Alaska at 07:01 UTC on 2022-09-07, 168 km deep.

· 168 km deep · released about 480 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 2.8 (ml)
Depth
168 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1461 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. 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 2018-10-30 — about 1,000 times the energy of this one.

Before 2016, the USGS record lists 18 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 174 km W of Adak, Alaska · 43 km SE of this epicentre
  2. 6.4 187 km W of Adak, Alaska · 37 km SSE of this epicentre
  3. 6.2 230 km W of Adak, Alaska · 29 km WSW of this epicentre
  4. 5.8 224 km W of Adak, Alaska · 42 km SSW of this epicentre
  5. 5.8 184 km W of Adak, Alaska · 38 km SSE 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 52.1472, -179.6211. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.1 Andreanof Islands, Aleutian Islands, Alaska
  2. 2.7 198 km W of Adak, Alaska
  3. 2.6 230 km W of Adak, Alaska
  4. 3.0 228 km W of Adak, Alaska
  5. 2.5 187 km W of Adak, Alaska
  6. 2.0 176 km W of Adak, Alaska
  7. 1.6 207 km W of Adak, Alaska
  8. 2.9 172 km W of Adak, Alaska
  9. 2.1 211 km W of Adak, Alaska
  10. 3.5 231 km W of Adak, Alaska
  11. 1.8 225 km W of Adak, Alaska
  12. 2.1 229 km W of Adak, Alaska
  13. 2.1 182 km W of Adak, Alaska
  14. 3.7 225 km W of Adak, Alaska
  15. 2.0 228 km W 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.