QuakeIndex

Earthquake · reviewed by a seismologist

M 5.0mb

124 km SW of Adak, Alaska

· 42 km deep · released about 480 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 5.0 (mb)
Depth
42 km below the surface
Felt
1 report · strongest reported intensity III
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. 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 51.2551, -178.1353. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.5 81 km WSW of Adak, Alaska
  2. 2.8 150 km WSW of Adak, Alaska
  3. 2.8 154 km SW of Adak, Alaska
  4. 1.9 110 km SW of Adak, Alaska
  5. 3.9 112 km SW of Adak, Alaska
  6. 1.7 86 km WSW of Adak, Alaska
  7. 3.0 103 km SW of Adak, Alaska
  8. 1.7 87 km WSW of Adak, Alaska
  9. 1.8 82 km WSW of Adak, Alaska
  10. 1.9 120 km SW of Adak, Alaska
  11. 1.9 149 km WSW of Adak, Alaska
  12. 1.6 97 km SW of Adak, Alaska
  13. 2.7 121 km SW of Adak, Alaska
  14. 1.9 130 km SW of Adak, Alaska
  15. 1.9 79 km WSW 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 6.5 on 2018-08-15 — it released about 180 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.