QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4ml

106 km W of False Pass, Alaska

Yes. A magnitude 3.4 earthquake was recorded 106 km W of False Pass, Alaska, at 1:24 am AKDT on 8 April 2023 (09:24 UTC), 238 km deep.

· 238 km deep · released about 1.9 tons 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 3.4 (ml)
Depth
238 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1250 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 1.9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 89,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,800× the energy of this one
  4. This earthquake M 3.4 about 1.9 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 4× more

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 4.9 on 2017-05-12 — about 180 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 55.0395, -165.0365. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.4 98 km W of False Pass, Alaska
  2. 1.1 85 km NE of Akutan, Alaska
  3. 3.0 65 km NNE of Akutan, Alaska
  4. 2.7 103 km W of False Pass, Alaska
  5. 4.1 95 km WNW of False Pass, Alaska
  6. 1.5 79 km WSW of False Pass, Alaska
  7. 2.1 91 km NNE of Akutan, Alaska
  8. 2.0 94 km NNE of Akutan, Alaska
  9. 2.9 80 km NE of Akutan, Alaska
  10. 2.1 109 km NNE of Akutan, Alaska
  11. 2.8 82 km NE of Akutan, Alaska
  12. 2.3 84 km NNE of Akutan, Alaska
  13. 2.8 100 km NNE of Akutan, Alaska
  14. 2.9 87 km WSW of False Pass, Alaska
  15. 2.6 91 km W 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.