QuakeIndex

Earthquake · reviewed by a seismologist

M 5.2mwr

148 km WSW of Adak, Alaska

· 35 km deep · released about 950 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 5.2 (mwr)
Depth
35 km below the surface
Felt
3 reports · strongest reported intensity III
Measured shaking
intensity II (ShakeMap)
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 458 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 950 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7.9× the energy of this one
  3. Magna, Utah 2020 M 5.7 5.6× the energy of this one
  4. This earthquake M 5.2 about 950 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2,000× 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 51.1962, -178.4701. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.6 141 km WSW of Adak, Alaska
  2. 1.6 133 km SW of Adak, Alaska
  3. 2.1 126 km WSW of Adak, Alaska
  4. 2.9 140 km SW of Adak, Alaska
  5. 2.1 130 km WSW of Adak, Alaska
  6. 3.0 123 km SW of Adak, Alaska
  7. 2.2 145 km WSW of Adak, Alaska
  8. 2.9 144 km WSW of Adak, Alaska
  9. 2.2 147 km WSW of Adak, Alaska
  10. 1.9 141 km WSW of Adak, Alaska
  11. 1.7 129 km WSW of Adak, Alaska
  12. 3.3 122 km WSW of Adak, Alaska
  13. 1.9 119 km WSW of Adak, Alaska
  14. 1.9 147 km WSW of Adak, Alaska
  15. 2.2 150 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 89 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.