228 km SE of Chiniak, Alaska

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 3 people have reported feeling it to USGS.

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 56.4812, -149.1477. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.3 237 km SE of Chiniak, Alaska 22:29 UTC
2. 3.6 251 km SE of Chiniak, Alaska 22:27 UTC
3. 3.5 232 km SE of Chiniak, Alaska 21:51 UTC
4. 3.2 246 km SE of Chiniak, Alaska 21:25 UTC
5. 3.7 240 km SE of Chiniak, Alaska 21:09 UTC
6. 3.0 249 km ESE of Chiniak, Alaska 21:01 UTC
7. 3.5 263 km SE of Chiniak, Alaska 20:57 UTC
8. 4.4 252 km SE of Chiniak, Alaska 20:41 UTC
9. 3.3 233 km SE of Chiniak, Alaska 20:23 UTC
10. 4.2 242 km SE of Chiniak, Alaska 20:20 UTC
11. 3.2 248 km SE of Chiniak, Alaska 19:59 UTC
12. 3.7 251 km SE of Chiniak, Alaska 19:40 UTC
13. 3.6 218 km SE of Chiniak, Alaska 19:33 UTC
14. 3.5 247 km SE of Chiniak, Alaska 18:35 UTC
15. 3.8 230 km SE of Chiniak, Alaska 18:23 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 22:10 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 5.0 on 2018-01-23.

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.