QuakeIndex

Earthquake · reviewed by a seismologist

M 5.0mww

217 km SSE of Old Harbor, Alaska

· 13 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 (mww)
Depth
13 km below the surface
Felt
1 report · strongest reported intensity II
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 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 55.5493, -151.4274. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.5 229 km SSE of Old Harbor, Alaska
  2. 2.5 194 km SSE of Old Harbor, Alaska
  3. 2.8 228 km SSE of Old Harbor, Alaska
  4. 3.2 203 km SSE of Old Harbor, Alaska
  5. 2.8 205 km SSE of Old Harbor, Alaska
  6. 2.5 168 km SSE of Old Harbor, Alaska
  7. 2.4 218 km SSE of Old Harbor, Alaska
  8. 3.0 202 km SSE of Old Harbor, Alaska
  9. 3.5 206 km SSE of Old Harbor, Alaska
  10. 3.3 264 km SSE of Old Harbor, Alaska
  11. 2.9 195 km SE of Old Harbor, Alaska
  12. 2.5 181 km SSE of Old Harbor, Alaska
  13. 2.4 180 km SSE of Old Harbor, Alaska
  14. 2.5 218 km SSE of Old Harbor, Alaska
  15. 2.3 217 km SSE of Old Harbor, 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 4.7 on 2017-08-12.

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

On USGS

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