Andreanof Islands, Aleutian Islands, Alaska

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 1 person has 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 52.3968, -179.4074. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.9 216 km W of Adak, Alaska 20:12 UTC
2. 2.7 175 km WNW of Adak, Alaska 19:36 UTC
3. 2.7 173 km W of Adak, Alaska 14:16 UTC
4. 2.6 167 km W of Adak, Alaska 17:09 UTC
5. 2.1 173 km W of Adak, Alaska 12:00 UTC
6. 2.0 187 km WNW of Adak, Alaska 21:06 UTC
7. 3.1 170 km WNW of Adak, Alaska 02:42 UTC
8. 2.5 184 km W of Adak, Alaska 09:38 UTC
9. 2.5 172 km WNW of Adak, Alaska 18:01 UTC
10. 2.4 197 km WNW of Adak, Alaska 11:58 UTC
11. 2.7 218 km W of Adak, Alaska 23:56 UTC
12. 4.0 169 km WNW of Adak, Alaska 08:07 UTC
13. 3.7 184 km WNW of Adak, Alaska 20:43 UTC
14. 3.0 166 km W of Adak, Alaska 16:31 UTC
15. 3.2 204 km W of Adak, Alaska 10:21 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 06:00 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 5.7 on 2018-02-08 — it released about 45 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.