QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

214 km W of Adak, Alaska

Yes. A magnitude 3.0 earthquake was recorded 214 km W of Adak, Alaska at 23:12 UTC on 2023-09-04, 106 km deep.

· 106 km deep · released about 950 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 3.0 (ml)
Depth
106 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1094 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 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 350,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
  4. This earthquake M 3.0 about 950 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 5.2 on 2016-11-23 — about 2,000 times the energy of this one.

Before 2016, the USGS record lists 39 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 207 km WSW of Adak, Alaska · 49 km SSE of this epicentre
  2. 6.7 237 km WSW of Adak, Alaska · 50 km SSW of this epicentre
  3. 6.7 205 km WSW of Adak, Alaska · 29 km SSE of this epicentre
  4. 6.7 227 km WSW of Adak, Alaska · 41 km S of this epicentre
  5. 6.7 221 km WSW of Adak, Alaska · 30 km S 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 51.7785, -179.7404. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.0 204 km WSW of Adak, Alaska
  2. 2.3 223 km WSW of Adak, Alaska
  3. 2.6 194 km WSW of Adak, Alaska
  4. 3.4 217 km W of Adak, Alaska
  5. 2.7 200 km WSW of Adak, Alaska
  6. 2.4 228 km WSW of Adak, Alaska
  7. 2.2 205 km WSW of Adak, Alaska
  8. 2.3 208 km WSW of Adak, Alaska
  9. 2.7 208 km WSW of Adak, Alaska
  10. 2.0 211 km W of Adak, Alaska
  11. 2.9 207 km W of Adak, Alaska
  12. 2.8 192 km W of Adak, Alaska
  13. 2.6 209 km W of Adak, Alaska
  14. 2.8 231 km W of Adak, Alaska
  15. 2.7 197 km WSW 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.