QuakeIndex

Earthquake · reviewed by a seismologist

M 5.1mww

208 km SSE of Atka, Alaska

· 29 km deep · released about 670 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 5.1 (mww)
Depth
29 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 624 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

How big was it?

This earthquake released about 670 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11× the energy of this one
  3. Magna, Utah 2020 M 5.7 7.9× the energy of this one
  4. This earthquake M 5.1 about 670 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 1,400× 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 50.6010, -172.6287. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.3 201 km SSE of Atka, Alaska
  2. 4.6 188 km SSE of Atka, Alaska
  3. 3.8 187 km SSE of Atka, Alaska
  4. 3.2 169 km SSE of Atka, Alaska
  5. 3.3 213 km SE of Atka, Alaska
  6. 3.7 195 km SE of Atka, Alaska
  7. 3.8 176 km SSE of Atka, Alaska
  8. 3.1 205 km SSE of Atka, Alaska
  9. 3.7 176 km SSE of Atka, Alaska
  10. 3.0 228 km SSE of Atka, Alaska
  11. 2.8 177 km SSE of Atka, Alaska
  12. 2.9 189 km SSE of Atka, Alaska
  13. 3.5 206 km SSE of Atka, Alaska
  14. 2.9 182 km SSE of Atka, Alaska
  15. 2.9 199 km SSE of Atka, 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 4.2 on 2017-11-29.

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

On USGS

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