QuakeIndex

Earthquake · reviewed by a seismologist

M 3.8ml

121 km WSW of Akhiok, Alaska

· 63 km deep · released about 7.6 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 3.8 (ml)
Depth
63 km below the surface
Felt
no reports yet
Measured shaking
intensity II (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2346 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 7.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 22,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 710× the energy of this one
  4. This earthquake M 3.8 about 7.6 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 16× 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.

Where

Epicentre 56.3673, -155.8552. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.5 105 km WSW of Akhiok, Alaska
  2. 1.6 90 km WSW of Akhiok, Alaska
  3. 1.8 124 km SE of Ugashik, Alaska
  4. 1.6 111 km W of Akhiok, Alaska
  5. 2.2 111 km SE of Ugashik, Alaska
  6. 2.5 152 km SW of Akhiok, Alaska
  7. 3.3 98 km WSW of Akhiok, Alaska
  8. 1.8 133 km SW of Akhiok, Alaska
  9. 1.9 97 km WSW of Akhiok, Alaska
  10. 1.9 130 km ESE of Chignik, Alaska
  11. 4.2 130 km ESE of Chignik, Alaska
  12. 2.0 135 km SW of Akhiok, Alaska
  13. 2.3 124 km WSW of Akhiok, Alaska
  14. 2.8 104 km WSW of Akhiok, Alaska
  15. 2.6 132 km ESE of Chignik, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.5 on 2017-03-28 — it released about 11 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.