QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

2 km NE of Adak, Alaska

Yes. A magnitude 1.5 earthquake was recorded 2 km NE of Adak, Alaska at 07:38 UTC on 2022-06-20, 5.9 km deep.

· 5.9 km deep · released about 5.9 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 1.5 (ml)
Depth
5.9 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1607 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 9 km (6 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 5.9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 5.2 on 2018-02-16 — about 320,000 times the energy of this one.

Before 2016, the USGS record lists 85 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.6 5 km WNW of Adak, Alaska · 7 km W of this epicentre
  2. 7.3 46 km SSW of Adak, Alaska · 49 km SSW of this epicentre
  3. 6.5 46 km ESE of Adak, Alaska · 44 km ESE of this epicentre
  4. 6.4 20 km SSW of Adak, Alaska · 23 km SSW of this epicentre
  5. 6.3 52 km ENE of Adak, Alaska · 49 km ENE 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 51.8900, -176.5995. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.0 47 km NE of Adak, Alaska
  2. 1.6 44 km SSE of Adak, Alaska
  3. 1.5 29 km SSW of Adak, Alaska
  4. 1.6 43 km SE of Adak, Alaska
  5. 1.5 13 km NNW of Adak, Alaska
  6. 1.6 39 km E of Adak, Alaska
  7. 1.6 4 km NNW of Adak, Alaska
  8. 1.5 24 km SSW of Adak, Alaska
  9. 1.7 44 km SW of Adak, Alaska
  10. 2.7 45 km SSE of Adak, Alaska
  11. 1.7 12 km SSE of Adak, Alaska
  12. 1.6 14 km WSW of Adak, Alaska
  13. 2.2 29 km ENE of Adak, Alaska
  14. 3.1 46 km SSW of Adak, Alaska
  15. 3.5 48 km SSE 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.