QuakeIndex

Earthquake · reviewed by a seismologist

M 4.2ml

8 km NNE of Old Harbor, Alaska

· 39 km deep · released about 30 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Kodiak Island Borough 62 km
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 4.2 (ml)
Depth
39 km below the surface
Felt
38 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
Nearest
Kodiak Island Borough, 62 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 78 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 38 people have reported feeling it to USGS.

How big was it?

This earthquake released about 30 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 5,600× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 250× the energy of this one
  3. Magna, Utah 2020 M 5.7 180× the energy of this one
  4. This earthquake M 4.2 about 30 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 63× 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 57.2750, -153.2600. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Kodiak Island Borough, AK 62 km (38 mi) SE of here earthquakes near Kodiak Island Borough

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 2.4 25 km S of Womens Bay, Alaska
  2. 1.9 30 km SSE of Old Harbor, Alaska
  3. 1.8 23 km WNW of Old Harbor, Alaska
  4. 1.5 23 km NNW of Old Harbor, Alaska
  5. 3.2 24 km ENE of Akhiok, Alaska
  6. 2.1 34 km ENE of Larsen Bay, Alaska
  7. 2.1 37 km SW of Port Lions, Alaska
  8. 1.7 30 km N of Old Harbor, Alaska
  9. 2.4 35 km ESE of Old Harbor, Alaska
  10. 1.9 26 km SW of Old Harbor, Alaska
  11. 2.0 29 km WNW of Old Harbor, Alaska
  12. 1.9 30 km SE of Old Harbor, Alaska
  13. 1.8 11 km SE of Old Harbor, Alaska
  14. 2.7 36 km WSW of Womens Bay, Alaska
  15. 2.3 23 km ESE of Larsen Bay, 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 4.2 on 2024-12-12.

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

On USGS

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