QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

20 km SSE of Port Graham, Alaska

· 49 km deep · released about 340 lb 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 2.7 (ml)
Depth
49 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1150 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.8× the energy of this one
  4. This earthquake M 2.7 about 340 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 59.1838, -151.6867. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.9 17 km W of Nanwalek, Alaska
  2. 1.6 17 km ESE of Port Graham, Alaska
  3. 2.8 50 km SSW of Nanwalek, Alaska
  4. 1.5 Southern Alaska
  5. 2.1 34 km ESE of Port Graham, Alaska
  6. 1.7 51 km S of Port Graham, Alaska
  7. 1.7 19 km WSW of Nanwalek, Alaska
  8. 1.7 19 km SW of Nanwalek, Alaska
  9. 1.7 21 km NW of Seldovia Village, Alaska
  10. 1.5 18 km WNW of Nanwalek, Alaska
  11. 2.5 4 km WSW of Seldovia, Alaska
  12. 1.5 15 km NW of Nanwalek, Alaska
  13. 2.7 21 km ESE of Seldovia Village, Alaska
  14. 2.2 27 km SE of Seldovia Village, Alaska
  15. 1.9 14 km SSW of Nanwalek, 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.

On USGS

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