163 km S of False Pass, Alaska

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 8 km (5 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
2. Magna, Utah 2020 M 5.7 89,000× the energy of this one
3. Around the size people start to feel M 3.0 7.9× the energy of this one
4. This earthquake M 2.4 about 120 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.

For this area

The largest earthquake within 50 km since 2016 was M 5.9 on 2016-10-27 — about 180,000 times the energy of this one.

Before 2016, the USGS record lists 54 earthquakes of M5 or more within 50 km; the five largest:

1. 6.6 146 km ESE of Akutan, Alaska · 20 km NW of this epicentre Apr 1, 1946
2. 6.2 Unimak Island region, Alaska · 49 km NNW of this epicentre Oct 14, 1933
3. 6.2 136 km SE of Akutan, Alaska · 31 km W of this epicentre Apr 1, 1946
4. 6.2 136 km S of False Pass, Alaska · 30 km NNW of this epicentre Apr 2, 1946
5. 6.2 184 km SE of Akutan, Alaska · 24 km SSE of this epicentre Apr 6, 1946

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 53.3924, -163.6002. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.3 123 km ESE of Akutan, Alaska 08:59 UTC
2. 2.9 160 km S of False Pass, Alaska 08:24 UTC
3. 2.5 144 km SE of Akutan, Alaska 05:52 UTC
4. 3.9 152 km S of False Pass, Alaska 08:14 UTC
5. 3.1 136 km S of False Pass, Alaska 07:48 UTC
6. 3.1 159 km S of False Pass, Alaska 14:17 UTC
7. 2.4 148 km ESE of Akutan, Alaska 08:29 UTC
8. 2.3 125 km ESE of Akutan, Alaska 14:20 UTC
9. 2.4 145 km S of False Pass, Alaska 17:08 UTC
10. 2.9 163 km ESE of Akutan, Alaska 13:50 UTC
11. 2.6 141 km ESE of Akutan, Alaska 12:25 UTC
12. 2.6 165 km S of False Pass, Alaska 12:53 UTC
13. 2.3 159 km ESE of Akutan, Alaska 07:39 UTC
14. 2.1 162 km ESE of Akutan, Alaska 23:19 UTC
15. 2.4 169 km ESE of Akutan, Alaska 11:01 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 03:01 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

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.