QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

Andreanof Islands, Aleutian Islands, Alaska

Yes. A magnitude 3.0 earthquake was recorded in the Andreanof Islands, Aleutian Islands, Alaska at 16:10 UTC on 2018-03-24, 23 km deep.

· 23 km deep · released about 950 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 3.0 (ml)
Depth
23 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1188 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 28 km (17 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 350,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
  4. This earthquake M 3.0 about 950 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.

For this area

The largest earthquake within 50 km since 2016 was M 5.3 on 2017-05-28 — about 2,800 times the energy of this one.

Before 2016, the USGS record lists 193 earthquakes of M5 or more within 50 km; the five largest:

  1. 8.0 1986 Atka, Alaska Earthquake · 8 km ENE of this epicentre
  2. 7.0 101 km SW of Atka, Alaska · 24 km W of this epicentre
  3. 6.9 100 km ESE of Adak, Alaska · 28 km W of this epicentre
  4. 6.8 57 km SSW of Atka, Alaska · 38 km NE of this epicentre
  5. 6.8 99 km SW of Atka, Alaska · 17 km W of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 51.5003, -174.8869. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.0 Andreanof Islands, Aleutian Islands, Alaska
  2. 1.8 Andreanof Islands, Aleutian Islands, Alaska
  3. 1.9 81 km SW of Atka, Alaska
  4. 2.2 109 km SSW of Atka, Alaska
  5. 2.4 104 km ESE of Adak, Alaska
  6. 1.6 73 km SW of Atka, Alaska
  7. 3.0 59 km SSW of Atka, Alaska
  8. 1.9 97 km ESE of Adak, Alaska
  9. 1.7 65 km SW of Atka, Alaska
  10. 2.0 111 km SSW of Atka, Alaska
  11. 3.3 105 km S of Atka, Alaska
  12. 1.7 126 km SSW of Atka, Alaska
  13. 2.0 94 km SW of Atka, Alaska
  14. 1.6 57 km SW of Atka, Alaska
  15. 2.9 102 km ESE 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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.