QuakeIndex

Earthquake · reviewed by a seismologist

M 5.9mww

95 km SSW of Adak, Alaska

· 17 km deep · released about 11 kilotons 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 5.9 (mww)
Depth
17 km below the surface
Felt
no reports yet
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
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 1146 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 11 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.9 would have released about 32 times as much.

  1. Ridgecrest, California 2019 M 7.1 63× the energy of this one
  2. Loma Prieta, California 1989 M 6.9 32× the energy of this one
  3. Northridge, California 1994 M 6.7 16× the energy of this one
  4. This earthquake M 5.9 about 11 kilotons of TNT
  5. Mineral, Virginia 2011 M 5.8 this one released 1.4× more
  6. Magna, Utah 2020 M 5.7 this one released 2× 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 51.0450, -176.9868. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.6 61 km SW of Adak, Alaska
  2. 2.6 61 km S of Adak, Alaska
  3. 3.7 89 km SW of Adak, Alaska
  4. 2.8 104 km SSW of Adak, Alaska
  5. 1.8 51 km S of Adak, Alaska
  6. 1.9 60 km SSW of Adak, Alaska
  7. 1.8 68 km S of Adak, Alaska
  8. 3.5 98 km SSW of Adak, Alaska
  9. 2.9 107 km SSW of Adak, Alaska
  10. 2.3 101 km S of Adak, Alaska
  11. 3.2 113 km SSW of Adak, Alaska
  12. 3.0 108 km S of Adak, Alaska
  13. 3.1 109 km SSW of Adak, Alaska
  14. 2.3 100 km SSW of Adak, Alaska
  15. 2.1 102 km SSW of Adak, 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 5.7 on 2017-05-08.

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

On USGS

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