QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4ml

Earthquake near Unalaska, AK

No earthquake was likely felt in Unalaska in the 24 hours to 1:43 am AKST (10:43 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 3.4 earthquake was recorded 16 km (10 mi) east-northeast of Unalaska, AK, at 9:31 am AKDT on 1 September 2024 (17:31 UTC), 12 km deep. 2 people have reported feeling it to USGS.

USGS: 15 km ENE of Unalaska, Alaska

9:31 am AKDT, Sep 1, 2024 · · 12 km deep · released about 1.9 tons 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
9:31 am AKDT on 1 September 2024 ()
Where
16 km (10 mi) east-northeast of Unalaska, AK · earthquakes near Unalaska
Magnitude
M 3.4 (ml)
Depth
12 km below the surface
Felt
2 reports · strongest reported intensity III
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 735 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 56 km (35 mi) from the epicentre. In Unalaska, 16 km away, the estimate is intensity III (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.

Likely felt in: Unalaska 16 km, intensity III · Akutan 43 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 89,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,800× the energy of this one
  4. This earthquake M 3.4 about 1.9 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 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 5.4 on 2019-09-14 — about 1,000 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 39 km S of Akutan, Alaska · 38 km ESE of this epicentre
  2. 6.2 36 km ESE of Unalaska, Alaska · 27 km SE of this epicentre
  3. 5.9 27 km WNW of Dutch Harbor, Alaska · 41 km WNW of this epicentre
  4. 5.9 13 km NE of Dutch Harbor, Alaska · 9 km NW of this epicentre
  5. 5.5 52 km SE of Unalaska, Alaska · 44 km SE 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 53.9092, -166.3017. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.5 23 km ENE of Dutch Harbor, Alaska
  2. 2.0 32 km SSW of Unalaska, Alaska
  3. 2.0 36 km SE of Unalaska, Alaska
  4. 2.7 30 km SSW of Unalaska, Alaska
  5. 2.0 27 km SSW of Unalaska, Alaska
  6. 2.6 10 km WSW of Akutan, Alaska
  7. 1.9 43 km S of Akutan, Alaska
  8. 2.0 40 km S of Unalaska, Alaska
  9. 2.2 22 km W of Akutan, Alaska
  10. 2.8 45 km SE of Unalaska, Alaska
  11. 1.9 37 km S of Unalaska, Alaska
  12. 1.6 21 km SE of Unalaska, Alaska
  13. 3.0 21 km SSE of Unalaska, Alaska
  14. 1.9 23 km SW of Unalaska, Alaska
  15. 1.8 45 km S of Akutan, 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.