134 km S 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 1,900 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 53.6520, -163.2540. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 109 km SSE of False Pass, Alaska 14:05 UTC
2. 2.2 99 km SSE of False Pass, Alaska 22:52 UTC
3. 2.2 157 km ESE of Akutan, Alaska 20:41 UTC
4. 2.8 176 km SE of Akutan, Alaska 17:52 UTC
5. 3.1 155 km S of False Pass, Alaska 03:55 UTC
6. 2.9 153 km ESE of Akutan, Alaska 01:47 UTC
7. 2.3 102 km SSE of False Pass, Alaska 04:36 UTC
8. 2.4 100 km S of False Pass, Alaska 11:17 UTC
9. 2.6 113 km SSE of False Pass, Alaska 11:12 UTC
10. 2.2 112 km S of False Pass, Alaska 00:32 UTC
11. 2.9 138 km SSE of False Pass, Alaska 08:47 UTC
12. 2.9 102 km SSE of False Pass, Alaska 05:00 UTC
13. 2.8 134 km SSE of False Pass, Alaska 19:01 UTC
14. 2.5 125 km SSE of False Pass, Alaska 12:24 UTC
15. 2.4 108 km SSW of False Pass, Alaska 14:36 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:30 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.