112 km SSE of Ugashik, Alaska

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 2 people have reported feeling it to USGS.

How big was it?

This earthquake released about 120 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.6 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 1,400× the energy of this one
2. Mineral, Virginia 2011 M 5.8 63× the energy of this one
3. Magna, Utah 2020 M 5.7 45× the energy of this one
4. This earthquake M 4.6 about 120 tons of TNT
5. Around the size people start to feel M 3.0 this one released 250× 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.

Where

Epicentre 56.6497, -156.4305. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.9 122 km E of Chignik, Alaska 16:41 UTC
2. 1.9 117 km E of Chignik, Alaska 15:06 UTC
3. 2.2 103 km ENE of Chignik, Alaska 23:04 UTC
4. 1.6 78 km SSE of Ugashik, Alaska 20:14 UTC
5. 2.4 103 km E of Chignik, Alaska 09:03 UTC
6. 2.3 79 km SSE of Ugashik, Alaska 02:02 UTC
7. 1.6 121 km E of Chignik, Alaska 20:39 UTC
8. 1.6 107 km SE of Ugashik, Alaska 21:36 UTC
9. 1.8 118 km SE of Ugashik, Alaska 10:59 UTC
10. 4.2 113 km E of Chignik, Alaska 13:15 UTC
11. 3.0 114 km E of Chignik, Alaska 13:09 UTC
12. 2.1 101 km E of Chignik, Alaska 17:19 UTC
13. 1.9 75 km SE of Ugashik, Alaska 05:31 UTC
14. 1.9 109 km SSE of Ugashik, Alaska 17:56 UTC
15. 2.5 118 km E of Chignik, Alaska 20:41 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 08:48 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 6.9 on 2021-10-11 — it released about 2,800 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.