QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9ml

219 km SE of Chiniak, Alaska

· 22 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
22 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 56.1935, -149.7827. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.1 209 km SE of Chiniak, Alaska
  2. 3.4 206 km SE of Chiniak, Alaska
  3. 3.1 241 km SE of Chiniak, Alaska
  4. 3.4 222 km SSE of Chiniak, Alaska
  5. 3.3 219 km SE of Chiniak, Alaska
  6. 2.7 176 km SE of Chiniak, Alaska
  7. 3.1 229 km SE of Chiniak, Alaska
  8. 3.1 238 km SE of Chiniak, Alaska
  9. 4.2 237 km SE of Chiniak, Alaska
  10. 3.9 230 km SE of Chiniak, Alaska
  11. 3.5 254 km SE of Chiniak, Alaska
  12. 3.1 249 km SE of Chiniak, Alaska
  13. 3.1 211 km SE of Chiniak, Alaska
  14. 3.2 222 km SE of Chiniak, Alaska
  15. 3.1 243 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.