107 km ESE of Atka, 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 (31 mi) since our catalogue begins in 2016. The previous largest was M 4.2 on 2016-07-23.

Before 2016, the USGS record lists 26 earthquakes of M5 or more within 50 km; the five largest:

1. 6.5 95 km ESE of Atka, Alaska · 29 km SW of this epicentre Mar 10, 1957
2. 6.5 143 km ESE of Atka, Alaska · 36 km ESE of this epicentre Oct 14, 1960
3. 6.5 99 km SE of Atka, Alaska · 38 km SW of this epicentre Nov 9, 2015
4. 6.3 143 km E of Atka, Alaska · 42 km ENE of this epicentre Apr 5, 1957
5. 6.1 108 km SE of Atka, Alaska · 30 km SSW of this epicentre May 1, 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 51.9010, -172.7158. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.8 86 km ESE of Atka, Alaska 07:16 UTC
2. 3.5 125 km E of Atka, Alaska 07:43 UTC
3. 2.6 107 km E of Atka, Alaska 01:26 UTC
4. 2.3 92 km SE of Atka, Alaska 03:56 UTC
5. 2.1 79 km ESE of Atka, Alaska 13:07 UTC
6. 2.1 82 km ESE of Atka, Alaska 05:33 UTC
7. 2.8 141 km ESE of Atka, Alaska 18:41 UTC
8. 2.1 73 km E of Atka, Alaska 21:45 UTC
9. 2.0 71 km E of Atka, Alaska 17:58 UTC
10. 3.3 129 km ESE of Atka, Alaska 03:39 UTC
11. 2.6 133 km ESE of Atka, Alaska 20:10 UTC
12. 2.5 131 km E of Atka, Alaska 02:05 UTC
13. 3.3 128 km ESE of Atka, Alaska 07:11 UTC
14. 2.1 84 km SE of Atka, Alaska 18:59 UTC
15. 2.0 88 km ESE of Atka, Alaska 05:41 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 07:29 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.