QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

183 km S of False Pass, Alaska

Yes. A magnitude 2.5 earthquake was recorded 183 km S of False Pass, Alaska at 02:33 UTC on 2025-04-08, 10 km deep.

· 10 km deep · released about 170 lb of TNT

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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 2.5 (ml)
Depth
10 km below the surface
Felt
no reports yet
Nearest mapped fault
Alaska-Aleutian subduction zone, 19 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 523 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 20 km (12 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 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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 5.9 on 2016-10-27 — about 130,000 times the energy of this one.

Before 2016, the USGS record lists 35 earthquakes of M5 or more within 50 km; the five largest:

  1. 8.6 The 1946 Unimak Island, Alaska Earthquake · 42 km NE of this epicentre
  2. 6.2 172 km SSE of False Pass, Alaska · 30 km ENE of this epicentre
  3. 6.2 184 km SE of Akutan, Alaska · 15 km W of this epicentre
  4. 6.1 166 km S of False Pass, Alaska · 20 km NNE of this epicentre
  5. 6.0 195 km S of False Pass, Alaska · 11 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 53.2052, -163.2428. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.7 152 km S of False Pass, Alaska
  2. 2.1 161 km S of False Pass, Alaska
  3. 3.0 156 km S of False Pass, Alaska
  4. 3.3 163 km ESE of Akutan, Alaska
  5. 2.0 160 km S of False Pass, Alaska
  6. 2.7 159 km S of False Pass, Alaska
  7. 2.1 170 km S of False Pass, Alaska
  8. 4.5 154 km ESE of Akutan, Alaska
  9. 2.1 160 km S of False Pass, Alaska
  10. 3.0 155 km S of False Pass, Alaska
  11. 2.2 162 km S of False Pass, Alaska
  12. 2.0 159 km S of False Pass, Alaska
  13. 2.5 157 km S of False Pass, Alaska
  14. 2.8 158 km S of False Pass, Alaska
  15. 2.6 160 km S 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.