QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

Earthquake near Unalaska, AK

No earthquake was likely felt in Unalaska in the 24 hours to 6:35 pm AKST (03:35 UTC). The last one was M 4.4, 117 km (72 mi) ESE, at 3:00 pm AKST on 11 November 2026, estimated intensity II (weak) in town. Every earthquake near Unalaska

This page: a magnitude 3.1 earthquake was recorded 46 km (29 mi) south-southwest of Unalaska, AK, at 12:42 am AKDT on 16 May 2022 (08:42 UTC), 78 km deep.

USGS: 46 km SSW of Unalaska, Alaska

12:42 am AKDT, May 16, 2022 · · 78 km deep · released about 1,300 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
12:42 am AKDT on 16 May 2022 ()
Where
46 km (29 mi) south-southwest of Unalaska, AK · earthquakes near Unalaska
Magnitude
M 3.1 (ml)
Depth
78 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1574 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 it was probably too small to be felt, even directly above it. In Unalaska, 46 km away, the estimate is intensity II (weak). 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× more

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 6.2 on 2022-01-22 — about 45,000 times the energy of this one.

Before 2016, the USGS record lists 27 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 67 km SW of Unalaska, Alaska · 35 km W of this epicentre
  2. 6.8 68 km SSW of Unalaska, Alaska · 23 km SSW of this epicentre
  3. 6.2 74 km SSW of Unalaska, Alaska · 28 km SSW of this epicentre
  4. 6.1 56 km SSW of Unalaska, Alaska · 10 km S of this epicentre
  5. 6.1 63 km SSW of Unalaska, Alaska · 18 km SSW 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 53.4829, -166.7651. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.7 54 km SW of Unalaska, Alaska
  2. 1.6 31 km SW of Unalaska, Alaska
  3. 1.6 Fox Islands, Aleutian Islands, Alaska
  4. 2.0 89 km SSW of Unalaska, Alaska
  5. 2.6 72 km S of Unalaska, Alaska
  6. 2.7 86 km SSW of Unalaska, Alaska
  7. 2.9 80 km S of Unalaska, Alaska
  8. 1.6 20 km W of Dutch Harbor, Alaska
  9. 1.6 42 km WSW of Unalaska, Alaska
  10. 2.5 21 km WSW of Unalaska, Alaska
  11. 1.7 60 km SW of Unalaska, Alaska
  12. 1.8 80 km SSW of Unalaska, Alaska
  13. 1.6 81 km SSW of Unalaska, Alaska
  14. 1.7 80 km SSW of Unalaska, Alaska
  15. 2.0 75 km S 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.

On USGS

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