QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

85 km SSE of Unalaska, Alaska

· 24 km deep · released about 15 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 1.8 (ml)
Depth
24 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1152 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 53.2254, -165.8292. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.8 67 km SSE of Unalaska, Alaska
  2. 2.1 76 km SSE of Akutan, Alaska
  3. 1.6 43 km SE of Unalaska, Alaska
  4. 2.3 62 km SE of Unalaska, Alaska
  5. 2.0 83 km SE of Unalaska, Alaska
  6. 2.2 91 km SSE of Unalaska, Alaska
  7. 2.1 101 km SE of Unalaska, Alaska
  8. 3.7 57 km SSE of Unalaska, Alaska
  9. 3.7 58 km SSE of Unalaska, Alaska
  10. 1.8 104 km SE of Unalaska, Alaska
  11. 1.8 68 km SE of Unalaska, Alaska
  12. 2.6 95 km SSE of Unalaska, Alaska
  13. 2.1 69 km SE of Unalaska, Alaska
  14. 1.8 40 km SSE of Unalaska, Alaska
  15. 1.9 70 km SE of Unalaska, 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.