160 km ESE of Akutan, Alaska

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

How big was it?

This earthquake released about 2.7 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.5 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 63× the energy of this one
2. Mineral, Virginia 2011 M 5.8 2.8× the energy of this one
3. Magna, Utah 2020 M 5.7 2× the energy of this one
4. This earthquake M 5.5 about 2.7 kilotons of TNT
5. Around the size people start to feel M 3.0 this one released 5,600× 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 53.4177, -163.6635. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.6 162 km ESE of Akutan, Alaska 01:25 UTC
2. 2.4 158 km ESE of Akutan, Alaska 03:23 UTC
3. 1.9 115 km ESE of Akutan, Alaska 13:15 UTC
4. 2.6 Unimak Island region, Alaska 05:50 UTC
5. 2.1 136 km ESE of Akutan, Alaska 11:44 UTC
6. 2.4 158 km S of False Pass, Alaska 16:00 UTC
7. 2.3 161 km S of False Pass, Alaska 20:28 UTC
8. 3.4 164 km S of False Pass, Alaska 06:31 UTC
9. 1.9 115 km ESE of Akutan, Alaska 11:36 UTC
10. 2.7 149 km ESE of Akutan, Alaska 22:09 UTC
11. 4.1 152 km ESE of Akutan, Alaska 01:01 UTC
12. 2.3 142 km SE of Akutan, Alaska 11:38 UTC
13. 2.3 152 km SE of Akutan, Alaska 09:20 UTC
14. 2.2 168 km S of False Pass, Alaska 06:54 UTC
15. 2.8 159 km S of False Pass, Alaska 11:14 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 11:34 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 4 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.