QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

173 km WSW of Adak, 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 1501 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 51.3879, -179.0214. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.7 158 km WSW of Adak, Alaska
  2. 1.7 183 km WSW of Adak, Alaska
  3. 1.5 202 km W of Adak, Alaska
  4. 1.8 196 km WSW of Adak, Alaska
  5. 2.8 192 km WSW of Adak, Alaska
  6. 1.9 150 km WSW of Adak, Alaska
  7. 2.8 154 km WSW of Adak, Alaska
  8. 1.9 164 km WSW of Adak, Alaska
  9. 1.9 204 km WSW of Adak, Alaska
  10. 1.9 135 km WSW of Adak, Alaska
  11. 1.8 153 km WSW of Adak, Alaska
  12. 2.5 208 km WSW of Adak, Alaska
  13. 1.6 159 km W of Adak, Alaska
  14. 2.8 197 km WSW of Adak, Alaska
  15. 3.5 167 km WSW of Adak, 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 6.2 on 2017-05-08 — it released about 4,000,000 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.