154 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 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 350,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
4. This earthquake M 3.0 about 950 lb of TNT

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 53.4700, -163.5505. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.4 118 km SSW of False Pass, Alaska 07:48 UTC
2. 1.6 120 km SSW of False Pass, Alaska 08:53 UTC
3. 2.0 114 km SSW of False Pass, Alaska 04:20 UTC
4. 2.2 126 km S of False Pass, Alaska 19:02 UTC
5. 2.6 167 km S of False Pass, Alaska 06:14 UTC
6. 2.4 160 km ESE of Akutan, Alaska 03:01 UTC
7. 2.4 165 km S of False Pass, Alaska 14:17 UTC
8. 2.5 164 km S of False Pass, Alaska 13:58 UTC
9. 2.3 154 km S of False Pass, Alaska 00:25 UTC
10. 3.2 157 km S of False Pass, Alaska 23:38 UTC
11. 2.2 157 km S of False Pass, Alaska 07:58 UTC
12. 2.2 158 km ESE of Akutan, Alaska 10:03 UTC
13. 2.4 161 km ESE of Akutan, Alaska 05:59 UTC
14. 3.7 143 km ESE of Akutan, Alaska 05:21 UTC
15. 3.5 159 km S of False Pass, Alaska 05:20 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 12:46 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 22,000 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.