QuakeIndex

Earthquake · reviewed by a seismologist

M 5.2mww

250 km ESE of Chiniak, Alaska

· 10 km deep · released about 950 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 5.2 (mww)
Depth
10 km below the surface
Felt
6 reports · strongest reported intensity III
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. 6 people have reported feeling it to USGS.

How big was it?

This earthquake released about 950 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7.9× the energy of this one
  3. Magna, Utah 2020 M 5.7 5.6× the energy of this one
  4. This earthquake M 5.2 about 950 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2,000× 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 56.5205, -148.6788. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.2 255 km ESE of Chiniak, Alaska
  2. 2.7 Gulf of Alaska
  3. 3.1 266 km ESE of Chiniak, Alaska
  4. 2.7 253 km ESE of Chiniak, Alaska
  5. 3.1 253 km ESE of Chiniak, Alaska
  6. 2.7 218 km ESE of Chiniak, Alaska
  7. 3.0 241 km SE of Chiniak, Alaska
  8. 3.4 244 km SE of Chiniak, Alaska
  9. 2.9 215 km ESE of Chiniak, Alaska
  10. 2.7 249 km SE of Chiniak, Alaska
  11. 2.7 258 km SE of Chiniak, Alaska
  12. 3.7 251 km SE of Chiniak, Alaska
  13. 3.1 239 km ESE of Chiniak, Alaska
  14. 3.2 251 km SE of Chiniak, Alaska
  15. 3.7 257 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 5.5 on 2018-05-08 — it released about 2.8 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.