QuakeIndex

Earthquake · reviewed by a seismologist

M 4.3mb

Earthquake near Akutan, AK

No earthquake was likely felt in Akutan in the 24 hours to 5:30 pm AKST (02:30 UTC). The last one was M 4.4, 84 km (52 mi) SE, at 3:00 pm AKST on 11 November 2026, estimated intensity II (weak) in town. Every earthquake near Akutan

This page: a magnitude 4.3 earthquake was recorded 47 km (29 mi) south-southeast of Akutan, AK, at 8:38 am AKST on 22 November 2017 (17:38 UTC), 55 km deep. 2 people have reported feeling it to USGS.

USGS: 47 km SSE of Akutan, Alaska

8:38 am AKST, Nov 22, 2017 · · 55 km deep · released about 43 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
8:38 am AKST on 22 November 2017 ()
Where
47 km (29 mi) south-southeast of Akutan, AK · earthquakes near Akutan
Magnitude
M 4.3 (mb)
Depth
55 km below the surface
Felt
2 reports · strongest reported intensity II
Measured shaking
intensity III (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1191 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 108 km (67 mi) from the epicentre. In Akutan, 47 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.

Likely felt in: Akutan 47 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 43 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 4,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 180× the energy of this one
  3. Magna, Utah 2020 M 5.7 130× the energy of this one
  4. This earthquake M 4.3 about 43 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 89× 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 4.8 on 2016-09-18 — about 5.6 times the energy of this one.

Before 2016, the USGS record lists 33 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.1 39 km S of Akutan, Alaska · 18 km WNW of this epicentre
  2. 6.5 59 km ESE of Akutan, Alaska · 41 km ENE of this epicentre
  3. 6.4 50 km SE of Akutan, Alaska · 21 km ENE of this epicentre
  4. 6.2 57 km SE of Unalaska, Alaska · 34 km SW of this epicentre
  5. 6.2 36 km ESE of Unalaska, Alaska · 37 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 53.7409, -165.4983. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.0 41 km SE of Akutan, Alaska
  2. 1.7 75 km SSE of Akutan, Alaska
  3. 1.9 43 km ESE of Unalaska, Alaska
  4. 1.9 51 km SE of Akutan, Alaska
  5. 3.5 53 km SE of Unalaska, Alaska
  6. 1.9 19 km SE of Akutan, Alaska
  7. 1.6 51 km SSE of Akutan, Alaska
  8. 2.3 76 km SE of Akutan, Alaska
  9. 2.2 56 km SSE of Akutan, Alaska
  10. 3.4 33 km E of Akutan, Alaska
  11. 1.8 83 km SSE of Akutan, Alaska
  12. 3.4 42 km ESE of Unalaska, Alaska
  13. 1.9 79 km SSE of Akutan, Alaska
  14. 1.7 77 km SE of Unalaska, Alaska
  15. 2.1 69 km SE 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.