QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9ml

236 km SE of Chiniak, Alaska

· 5.8 km deep · released about 11 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 3.9 (ml)
Depth
5.8 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1143 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 11 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 16,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 710× the energy of this one
  3. Magna, Utah 2020 M 5.7 500× the energy of this one
  4. This earthquake M 3.9 about 11 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 22× 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 55.8750, -150.0513. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.1 207 km SE of Chiniak, Alaska
  2. 3.6 224 km SE of Chiniak, Alaska
  3. 2.9 242 km SE of Chiniak, Alaska
  4. 2.7 231 km SE of Chiniak, Alaska
  5. 3.1 208 km SE of Chiniak, Alaska
  6. 3.1 227 km SE of Chiniak, Alaska
  7. 2.6 214 km SE of Chiniak, Alaska
  8. 2.9 207 km SE of Chiniak, Alaska
  9. 2.9 217 km SSE of Chiniak, Alaska
  10. 3.3 219 km SE of Chiniak, Alaska
  11. 2.9 228 km SE of Chiniak, Alaska
  12. 3.0 213 km SE of Chiniak, Alaska
  13. 3.0 220 km SE of Chiniak, Alaska
  14. 5.0 227 km SE of Chiniak, Alaska
  15. 3.0 220 km SE 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 5.0 on 2018-01-23 — it released about 45 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.