Andreanof Islands, Aleutian Islands, Alaska

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 670 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.1 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 250× the energy of this one
2. Mineral, Virginia 2011 M 5.8 11× the energy of this one
3. Magna, Utah 2020 M 5.7 7.9× the energy of this one
4. This earthquake M 5.1 about 670 tons of TNT
5. Around the size people start to feel M 3.0 this one released 1,400× 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 51.2863, -179.1427. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.7 210 km WSW of Adak, Alaska 15:32 UTC
2. 2.1 162 km WSW of Adak, Alaska 13:53 UTC
3. 2.0 192 km WSW of Adak, Alaska 23:13 UTC
4. 1.9 191 km WSW of Adak, Alaska 00:06 UTC
5. 1.8 152 km WSW of Adak, Alaska 16:29 UTC
6. 2.6 215 km WSW of Adak, Alaska 11:22 UTC
7. 1.7 203 km WSW of Adak, Alaska 11:44 UTC
8. 1.8 191 km WSW of Adak, Alaska 05:45 UTC
9. 1.9 227 km WSW of Adak, Alaska 21:33 UTC
10. 1.9 197 km WSW of Adak, Alaska 14:43 UTC
11. 1.8 176 km WSW of Adak, Alaska 05:25 UTC
12. 2.2 193 km WSW of Adak, Alaska 13:59 UTC
13. 4.0 208 km WSW of Adak, Alaska 11:31 UTC
14. 1.9 172 km WSW of Adak, Alaska 03:14 UTC
15. 3.0 218 km WSW of Adak, Alaska 09:15 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 11:22 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 6.1 on 2021-09-24 — it released about 32 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.