105 km ESE of Ugashik, 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 139 km (86 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 85 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.5 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 2,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 89× the energy of this one
3. Magna, Utah 2020 M 5.7 63× the energy of this one
4. This earthquake M 4.5 about 85 tons of TNT
5. Around the size people start to feel M 3.0 this one released 180× 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 4.3 on 2022-03-20.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

1. 5.5 64 km SW of Karluk, Alaska · 44 km ENE of this epicentre Nov 11, 1968
2. 5.4 115 km SSE of Ugashik, Alaska · 48 km SSW of this epicentre Jun 9, 1971
3. 5.3 74 km WSW of Akhiok, Alaska · 44 km SE of this epicentre Nov 26, 1983
4. 5.0 113 km SE of Ugashik, Alaska · 33 km SSW of this epicentre Dec 30, 2010
5. 5.0 96 km SE of Ugashik, Alaska · 21 km WSW of this epicentre Apr 5, 2013

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 57.0081, -155.9271. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.9 75 km WNW of Akhiok, Alaska 19:24 UTC
2. 2.9 92 km W of Akhiok, Alaska 22:57 UTC
3. 2.7 122 km SE of Ugashik, Alaska 03:01 UTC
4. 1.5 77 km ESE of Ugashik, Alaska 04:14 UTC
5. 1.6 Alaska Peninsula 21:23 UTC
6. 1.5 64 km ESE of Ugashik, Alaska 10:08 UTC
7. 2.1 109 km W of Akhiok, Alaska 21:43 UTC
8. 1.9 68 km SW of Karluk, Alaska 22:45 UTC
9. 1.9 75 km SE of Ugashik, Alaska 20:12 UTC
10. 2.6 93 km W of Akhiok, Alaska 06:14 UTC
11. 2.2 Alaska Peninsula 23:03 UTC
12. 1.5 71 km ESE of Ugashik, Alaska 17:29 UTC
13. 2.4 87 km W of Akhiok, Alaska 20:44 UTC
14. 1.6 106 km W of Akhiok, Alaska 07:09 UTC
15. 1.6 80 km ESE of Ugashik, Alaska 18:32 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:25 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.