74 km SSW of Nikolski, Alaska

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 125 km (78 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 60 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.4 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 2,800× the energy of this one
2. Mineral, Virginia 2011 M 5.8 130× the energy of this one
3. Magna, Utah 2020 M 5.7 89× the energy of this one
4. This earthquake M 4.4 about 60 tons of TNT
5. Around the size people start to feel M 3.0 this one released 130× 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 4.9 on 2016-04-02 — about 5.6 times the energy of this one.

Before 2016, the USGS record lists 150 earthquakes of M5 or more within 50 km; the five largest:

1. 7.1 35 km SW of Nikolski, Alaska · 41 km NNE of this epicentre Mar 11, 1957
2. 6.9 77 km SSW of Nikolski, Alaska · 6 km W of this epicentre Jan 23, 1935
3. 6.9 80 km SW of Nikolski, Alaska · 14 km W of this epicentre Mar 9, 1957
4. 6.9 Fox Islands, Aleutian Islands, Alaska · 8 km WNW of this epicentre Jul 27, 2015
5. 6.8 46 km SSW of Nikolski, Alaska · 29 km NNE of this epicentre Jul 22, 1933

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 52.3370, -169.3443. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.8 47 km WSW of Nikolski, Alaska 01:01 UTC
2. 2.7 114 km SSW of Nikolski, Alaska 18:32 UTC
3. 4.2 70 km S of Nikolski, Alaska 23:01 UTC
4. 2.5 91 km SSW of Nikolski, Alaska 20:18 UTC
5. 2.4 98 km SSW of Nikolski, Alaska 17:18 UTC
6. 2.2 91 km SSW of Nikolski, Alaska 06:27 UTC
7. 2.0 69 km SW of Nikolski, Alaska 09:17 UTC
8. 2.2 50 km SW of Nikolski, Alaska 19:19 UTC
9. 2.0 99 km SSW of Nikolski, Alaska 04:52 UTC
10. 1.7 52 km WSW of Nikolski, Alaska 21:56 UTC
11. 2.0 53 km SW of Nikolski, Alaska 14:44 UTC
12. 2.0 49 km WSW of Nikolski, Alaska 21:47 UTC
13. 2.4 108 km S of Nikolski, Alaska 04:39 UTC
14. 2.0 35 km SSW of Nikolski, Alaska 09:47 UTC
15. 2.2 101 km SSW of Nikolski, Alaska 09:56 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 20:56 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.