Earthquake near Dutch Harbor, AK

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. In Dutch Harbor, 11 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: Unalaska 12 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
3. Around the size people start to feel M 3.0 1.4× the energy of this one
4. This earthquake M 2.9 about 680 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 4.8 on 2020-03-30 — about 710 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

1. 7.1 39 km S of Akutan, Alaska · 47 km ESE of this epicentre Mar 22, 1957
2. 6.2 36 km ESE of Unalaska, Alaska · 36 km SE of this epicentre Dec 9, 1942
3. 5.9 27 km WNW of Dutch Harbor, Alaska · 32 km W of this epicentre Apr 21, 1972
4. 5.9 13 km NE of Dutch Harbor, Alaska · 3 km ENE of this epicentre Sep 1, 2006
5. 5.4 26 km WSW of Dutch Harbor, Alaska · 36 km WSW of this epicentre Oct 20, 1991

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 53.9588, -166.4257. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.1 41 km SSE of Unalaska, Alaska 20:26 UTC
2. 2.0 22 km SW of Unalaska, Alaska 13:29 UTC
3. 1.6 35 km ESE of Unalaska, Alaska 15:55 UTC
4. 2.2 Fox Islands, Aleutian Islands, Alaska 15:08 UTC
5. 1.5 6 km WSW of Unalaska, Alaska 22:05 UTC
6. 1.7 Fox Islands, Aleutian Islands, Alaska 13:12 UTC
7. 1.5 5 km WSW of Dutch Harbor, Alaska 14:55 UTC
8. 1.6 4 km NNE of Dutch Harbor, Alaska 16:18 UTC
9. 1.6 36 km SE of Unalaska, Alaska 08:06 UTC
10. 1.6 Fox Islands, Aleutian Islands, Alaska 01:25 UTC
11. 2.7 9 km ENE of Dutch Harbor, Alaska 16:56 UTC
12. 1.6 9 km NE of Dutch Harbor, Alaska 16:47 UTC
13. 1.9 9 km NE of Dutch Harbor, Alaska 16:47 UTC
14. 2.2 Fox Islands, Aleutian Islands, Alaska 16:42 UTC
15. 2.2 33 km SE of Unalaska, Alaska 06:58 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:01 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

• The official USGS event page — the source of record for every value above
• Did you feel it? Report it to USGS — reports go to USGS, not to us
• ShakeMap for this event, when USGS has produced one

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