111 km SSW of False Pass, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 130,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 5,600× the energy of this one
3. Magna, Utah 2020 M 5.7 4,000× the energy of this one
4. This earthquake M 3.3 about 1.3 tons of TNT
5. Around the size people start to feel M 3.0 this one released 2.8× 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 53.8992, -163.9352. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.5 91 km S of False Pass, Alaska 13:28 UTC
2. 2.7 94 km SSW of False Pass, Alaska 11:00 UTC
3. 2.2 96 km E of Akutan, Alaska 19:21 UTC
4. 2.6 94 km SSW of False Pass, Alaska 07:41 UTC
5. 2.6 93 km SSW of False Pass, Alaska 22:56 UTC
6. 2.4 102 km ESE of Akutan, Alaska 22:08 UTC
7. 2.6 95 km E of Akutan, Alaska 13:51 UTC
8. 2.7 100 km S of False Pass, Alaska 12:46 UTC
9. 2.3 97 km ESE of Akutan, Alaska 17:22 UTC
10. 2.5 120 km ESE of Akutan, Alaska 10:23 UTC
11. 3.0 121 km ESE of Akutan, Alaska 22:38 UTC
12. 3.3 112 km ESE of Akutan, Alaska 19:10 UTC
13. 3.4 119 km ESE of Akutan, Alaska 18:35 UTC
14. 2.8 126 km SSW of False Pass, Alaska 14:13 UTC
15. 3.1 110 km ESE of Akutan, Alaska 05:51 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 18:45 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 5.1 on 2021-01-11 — it released about 500 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.