QuakeIndex

Earthquake · reviewed by a seismologist

M 5.4mww

252 km ESE of Chiniak, Alaska

· 6.4 km deep · released about 1.9 kilotons 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 5.4 (mww)
Depth
6.4 km below the surface
Felt
1 report · strongest reported intensity I
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 279 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 1.9 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 89× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4× the energy of this one
  3. Magna, Utah 2020 M 5.7 2.8× the energy of this one
  4. This earthquake M 5.4 about 1.9 kilotons of TNT
  5. Around the size people start to feel M 3.0 this one released 4,000× 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 56.5153, -148.6434. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.2 253 km ESE of Chiniak, Alaska
  2. 2.6 245 km ESE of Chiniak, Alaska
  3. 2.8 251 km ESE of Chiniak, Alaska
  4. 3.0 250 km SE of Chiniak, Alaska
  5. 2.8 248 km ESE of Chiniak, Alaska
  6. 3.3 243 km SE of Chiniak, Alaska
  7. 2.8 209 km ESE of Chiniak, Alaska
  8. 3.5 209 km ESE of Chiniak, Alaska
  9. 3.5 256 km ESE of Chiniak, Alaska
  10. 2.9 250 km ESE of Chiniak, Alaska
  11. 2.7 252 km ESE of Chiniak, Alaska
  12. 3.0 239 km SE of Chiniak, Alaska
  13. 4.1 253 km SE of Chiniak, Alaska
  14. 2.9 233 km SE of Chiniak, Alaska
  15. 2.8 251 km ESE of Chiniak, 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 5.5 on 2018-01-23 — it released about 1.4 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.