QuakeIndex

Earthquake · reviewed by a seismologist

M 5.7mww

98 km SSW of Adak, Alaska

Yes. A magnitude 5.7 earthquake was recorded 98 km SSW of Adak, Alaska at 15:31 UTC on 2017-05-08, 17 km deep.

· 17 km deep · released about 5.4 kilotons 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 5.7 (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 1193 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 292 km (181 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 5.4 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.7 would have released about 32 times as much.

  1. Loma Prieta, California 1989 M 6.9 63× the energy of this one
  2. Northridge, California 1994 M 6.7 32× the energy of this one
  3. Mineral, Virginia 2011 M 5.8 1.4× the energy of this one
  4. This earthquake M 5.7 about 5.4 kilotons of TNT
  5. Around the size people start to feel M 3.0 this one released 11,000× 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.

For this area

The largest earthquake within 50 km (31 mi) since our catalogue begins in 2016. The previous largest was M 4.6 on 2017-03-10.

Before 2016, the USGS record lists 75 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 75 km S of Adak, Alaska · 27 km NE of this epicentre
  2. 7.0 101 km S of Adak, Alaska · 47 km E of this epicentre
  3. 7.0 69 km SW of Adak, Alaska · 47 km NNW of this epicentre
  4. 6.9 61 km SSW of Adak, Alaska · 37 km NNE of this epicentre
  5. 6.8 90 km SSW of Adak, Alaska · 8 km NNE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 51.0251, -177.0116. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.8 104 km SSW of Adak, Alaska
  2. 1.9 60 km SSW of Adak, Alaska
  3. 1.8 68 km S of Adak, Alaska
  4. 3.5 98 km SSW of Adak, Alaska
  5. 2.9 107 km SSW of Adak, Alaska
  6. 2.3 101 km S of Adak, Alaska
  7. 3.2 113 km SSW of Adak, Alaska
  8. 3.0 108 km S of Adak, Alaska
  9. 3.1 109 km SSW of Adak, Alaska
  10. 2.3 100 km SSW of Adak, Alaska
  11. 2.1 102 km SSW of Adak, Alaska
  12. 2.1 93 km SSW of Adak, Alaska
  13. 3.1 108 km S of Adak, Alaska
  14. 3.2 105 km SSW of Adak, Alaska
  15. 3.2 108 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.

On USGS

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