QuakeIndex

Earthquake · reviewed by a seismologist

M 5.0mww

129 km E of Atka, Alaska

· 30 km deep · released about 480 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N
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 5.0 (mww)
Depth
30 km below the surface
Felt
1 report · strongest reported intensity IV
Measured shaking
intensity III (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 344 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 480 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 350× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 16× the energy of this one
  3. Magna, Utah 2020 M 5.7 11× the energy of this one
  4. This earthquake M 5.0 about 480 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 1,000× 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 52.0015, -172.3426. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.7 121 km ESE of Atka, Alaska
  2. 2.7 120 km E of Atka, Alaska
  3. 3.1 128 km E of Atka, Alaska
  4. 3.3 139 km E of Atka, Alaska
  5. 2.1 105 km ESE of Atka, Alaska
  6. 2.2 127 km ENE of Atka, Alaska
  7. 2.7 92 km E of Atka, Alaska
  8. 2.9 121 km E of Atka, Alaska
  9. 2.9 109 km E of Atka, Alaska
  10. 2.8 121 km E of Atka, Alaska
  11. 2.9 145 km ESE of Atka, Alaska
  12. 3.2 150 km ESE of Atka, Alaska
  13. 2.9 97 km E of Atka, Alaska
  14. 2.1 111 km ESE of Atka, Alaska
  15. 2.0 107 km ESE 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 4.6 on 2021-06-30.

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

On USGS

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