QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

147 km SSE of Unalaska, Alaska

· 10 km deep · released about 480 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 2.8 (ml)
Depth
10 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2591 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 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 52.6941, -165.5175. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.9 173 km SSE of Unalaska, Alaska
  2. 2.4 172 km SE of Unalaska, Alaska
  3. 3.8 161 km SSE of Unalaska, Alaska
  4. 1.9 131 km SSE of Unalaska, Alaska
  5. 2.2 116 km SSE of Unalaska, Alaska
  6. 1.8 159 km SSE of Unalaska, Alaska
  7. 1.6 117 km SSE of Akutan, Alaska
  8. 2.1 171 km SE of Unalaska, Alaska
  9. 2.0 152 km SSE of Unalaska, Alaska
  10. 2.1 190 km SSE of Unalaska, Alaska
  11. 1.9 105 km SE of Unalaska, Alaska
  12. 1.9 153 km SSE of Unalaska, Alaska
  13. 2.0 114 km SE of Unalaska, Alaska
  14. 1.7 south of the Aleutian Islands
  15. 2.0 110 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.3 on 2018-02-24 — it released about 180 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.