104 km SE of Ugashik, Alaska

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 2 km (1 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
3. Around the size people start to feel M 3.0 180× the energy of this one
4. This earthquake M 1.5 about 5.4 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 4.6 on 2022-04-10 — about 45,000 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

1. 6.8 117 km SSE of Ugashik, Alaska · 49 km SSW of this epicentre May 29, 2015
2. 5.4 115 km SSE of Ugashik, Alaska · 42 km SSW of this epicentre Jun 9, 1971
3. 5.4 113 km SSE of Ugashik, Alaska · 49 km SW of this epicentre Jan 27, 2004
4. 5.3 74 km WSW of Akhiok, Alaska · 45 km ESE of this epicentre Nov 26, 1983
5. 5.0 113 km SE of Ugashik, Alaska · 28 km SSW of this epicentre Dec 30, 2010

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 56.9676, -155.9916. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.3 81 km WSW of Karluk, Alaska 11:55 UTC
2. 2.7 122 km WSW of Akhiok, Alaska 04:20 UTC
3. 1.8 94 km SE of Ugashik, Alaska 08:50 UTC
4. 1.8 96 km SE of Ugashik, Alaska 00:51 UTC
5. 1.8 77 km SE of Ugashik, Alaska 13:07 UTC
6. 2.1 71 km ESE of Ugashik, Alaska 15:29 UTC
7. 2.1 Alaska Peninsula 22:37 UTC
8. 1.5 71 km ESE of Ugashik, Alaska 12:28 UTC
9. 2.2 87 km E of Ugashik, Alaska 12:37 UTC
10. 1.7 70 km ESE of Ugashik, Alaska 05:21 UTC
11. 1.7 74 km SE of Ugashik, Alaska 04:42 UTC
12. 1.8 91 km WSW of Karluk, Alaska 21:02 UTC
13. 1.8 91 km W of Akhiok, Alaska 20:59 UTC
14. 1.7 111 km WSW of Akhiok, Alaska 04:50 UTC
15. 2.1 Alaska Peninsula 16:42 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 04:01 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.