154 km S of False Pass, Alaska

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 5 people have 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 53.4698, -163.5246. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.8 150 km S of False Pass, Alaska 06:59 UTC
2. 4.5 Unimak Island region, Alaska 05:20 UTC
3. 4.3 146 km S of False Pass, Alaska 05:10 UTC
4. 2.5 123 km ESE of Akutan, Alaska 05:03 UTC
5. 4.3 120 km ESE of Akutan, Alaska 10:43 UTC
6. 4.5 122 km ESE of Akutan, Alaska 09:56 UTC
7. 4.8 120 km ESE of Akutan, Alaska 09:33 UTC
8. 2.8 120 km S of False Pass, Alaska 05:58 UTC
9. 2.8 123 km ESE of Akutan, Alaska 19:55 UTC
10. 3.3 122 km ESE of Akutan, Alaska 17:19 UTC
11. 2.5 115 km S of False Pass, Alaska 08:09 UTC
12. 2.2 154 km S of False Pass, Alaska 20:45 UTC
13. 2.4 160 km S of False Pass, Alaska 14:03 UTC
14. 4.4 153 km S of False Pass, Alaska 06:42 UTC
15. 3.3 154 km S of False Pass, Alaska 06:28 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:38 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 5.9 on 2016-10-27 — it released about 16 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.