266 km SSW of Nikolski, Alaska

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

How big was it?

This earthquake released about 85 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.5 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 2,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 89× the energy of this one
3. Magna, Utah 2020 M 5.7 63× the energy of this one
4. This earthquake M 4.5 about 85 tons of TNT
5. Around the size people start to feel M 3.0 this one released 180× 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 50.8433, -170.7295. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.0 243 km SSW of Nikolski, Alaska 07:51 UTC
2. 3.1 265 km SE of Atka, Alaska 22:10 UTC
3. 3.2 217 km SSW of Nikolski, Alaska 21:58 UTC
4. 2.9 282 km SSW of Nikolski, Alaska 04:42 UTC
5. 3.3 272 km SSW of Nikolski, Alaska 14:19 UTC
6. 2.8 270 km SSW of Nikolski, Alaska 06:38 UTC
7. 3.7 234 km SW of Nikolski, Alaska 13:52 UTC
8. 2.5 238 km ESE of Atka, Alaska 14:49 UTC
9. 3.8 280 km SSW of Nikolski, Alaska 12:07 UTC
10. 3.9 217 km SSW of Nikolski, Alaska 18:36 UTC
11. 2.9 248 km ESE of Atka, Alaska 06:46 UTC
12. 3.7 243 km SE of Atka, Alaska 00:25 UTC
13. 3.9 263 km SE of Atka, Alaska 00:22 UTC
14. 2.7 south of the Aleutian Islands 09:55 UTC
15. 2.9 259 km SSW of Nikolski, Alaska 09:00 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 19:01 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 5.8 on 2020-08-16 — it released about 89 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.