QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

73 km WSW of Unalaska, Alaska

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

USGS · last changed by USGS · we first saw it 1151 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 53.5184, -167.4778. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.8 78 km SW of Unalaska, Alaska
  2. 1.5 54 km SW of Unalaska, Alaska
  3. 1.6 89 km W of Dutch Harbor, Alaska
  4. 1.6 88 km SW of Unalaska, Alaska
  5. 2.1 83 km WSW of Unalaska, Alaska
  6. 1.9 51 km SW of Unalaska, Alaska
  7. 1.5 72 km WSW of Unalaska, Alaska
  8. 1.5 68 km SW of Unalaska, Alaska
  9. 2.1 72 km WSW of Dutch Harbor, Alaska
  10. 2.8 90 km W of Dutch Harbor, Alaska
  11. 1.8 73 km WSW of Unalaska, Alaska
  12. 1.6 Fox Islands, Aleutian Islands, Alaska
  13. 1.8 Fox Islands, Aleutian Islands, Alaska
  14. 1.7 72 km WSW of Unalaska, Alaska
  15. 1.9 69 km WSW 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.