QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

89 km SW of Atka, Alaska

· 26 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
26 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1117 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 51.5923, -175.0670. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.6 116 km SE of Adak, Alaska
  2. 4.7 120 km SE of Adak, Alaska
  3. 3.0 114 km SE of Adak, Alaska
  4. 4.6 119 km SE of Adak, Alaska
  5. 2.7 107 km ESE of Adak, Alaska
  6. 3.1 109 km SE of Adak, Alaska
  7. 2.8 108 km SE of Adak, Alaska
  8. 2.9 110 km SE of Adak, Alaska
  9. 3.2 113 km SE of Adak, Alaska
  10. 2.6 109 km SE of Adak, Alaska
  11. 2.7 99 km ESE of Adak, Alaska
  12. 3.3 108 km ESE of Adak, Alaska
  13. 6.1 116 km SE of Adak, Alaska
  14. 2.5 66 km WSW of Atka, Alaska
  15. 2.1 57 km SSW of Atka, 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 6.3 on 2019-11-24 — it released about 5,600,000 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.