146 km SSE of Adak, 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 50.6415, -175.8798. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 154 km S of Adak, Alaska 02:21 UTC
2. 2.1 126 km SSE of Adak, Alaska 12:45 UTC
3. 3.2 98 km SSE of Adak, Alaska 16:05 UTC
4. 1.6 147 km SSE of Adak, Alaska 14:13 UTC
5. 1.6 158 km SSE of Adak, Alaska 17:34 UTC
6. 1.9 157 km S of Adak, Alaska 06:09 UTC
7. 2.1 153 km SSE of Adak, Alaska 09:32 UTC
8. 3.0 187 km SSE of Adak, Alaska 19:19 UTC
9. 1.8 Andreanof Islands, Aleutian Islands, Alaska 15:45 UTC
10. 2.5 163 km SSE of Adak, Alaska 15:52 UTC
11. 2.3 161 km SSE of Adak, Alaska 03:49 UTC
12. 2.6 170 km SSE of Adak, Alaska 05:43 UTC
13. 2.1 167 km S of Adak, Alaska 02:43 UTC
14. 2.1 164 km S of Adak, Alaska 02:41 UTC
15. 2.8 172 km S of Adak, Alaska 00:36 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 00:01 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 5.0 on 2016-06-29 — it released about 5.6 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.