QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4ml

125 km SE of Port Graham, Alaska

· 47 km deep · released about 120 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N
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 2.4 (ml)
Depth
47 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1338 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 89,000× the energy of this one
  3. Around the size people start to feel M 3.0 7.9× the energy of this one
  4. This earthquake M 2.4 about 120 lb of TNT

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 58.4972, -150.4100. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.0 97 km SE of Port Graham, Alaska
  2. 2.3 116 km ENE of Kodiak, Alaska
  3. 2.4 112 km ENE of Ouzinkie, Alaska
  4. 2.2 123 km SE of Port Graham, Alaska
  5. 3.0 99 km ENE of Kodiak, Alaska
  6. 3.3 107 km ENE of Ouzinkie, Alaska
  7. 2.0 121 km SE of Port Graham, Alaska
  8. 3.4 121 km SE of Port Graham, Alaska
  9. 1.8 106 km ENE of Ouzinkie, Alaska
  10. 1.8 106 km ENE of Ouzinkie, Alaska
  11. 2.0 108 km ENE of Kodiak, Alaska
  12. 2.0 100 km ENE of Kodiak, Alaska
  13. 1.8 110 km SSE of Port Graham, Alaska
  14. 1.9 99 km SSE of Halibut Cove, Alaska
  15. 2.4 135 km ENE of Ouzinkie, 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 2020-10-10 — it released about 2,800 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.