161 km ESE of Akutan, 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 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 180,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
4. This earthquake M 3.2 about 1,900 lb of TNT
5. Around the size people start to feel M 3.0 this one released 2× 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 53.3500, -163.7251. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.5 127 km S of False Pass, Alaska 13:53 UTC
2. 3.3 153 km S of False Pass, Alaska 10:49 UTC
3. 2.4 154 km S of False Pass, Alaska 11:36 UTC
4. 2.3 161 km S of False Pass, Alaska 05:20 UTC
5. 2.6 174 km S of False Pass, Alaska 11:54 UTC
6. 3.7 150 km S of False Pass, Alaska 02:51 UTC
7. 4.0 162 km S of False Pass, Alaska 02:07 UTC
8. 2.0 146 km ESE of Akutan, Alaska 09:40 UTC
9. 2.3 165 km S of False Pass, Alaska 08:01 UTC
10. 2.3 158 km ESE of Akutan, Alaska 01:32 UTC
11. 2.3 152 km ESE of Akutan, Alaska 17:54 UTC
12. 3.2 162 km S of False Pass, Alaska 15:36 UTC
13. 3.3 160 km S of False Pass, Alaska 08:47 UTC
14. 3.3 158 km S of False Pass, Alaska 22:37 UTC
15. 3.3 152 km S of False Pass, Alaska 09:34 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:40 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 11,000 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.