116 km SSW 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 3 km (2 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 5.7 on 2020-08-13 — about 89,000 times the energy of this one.

Before 2016, the USGS record lists 63 earthquakes of M5 or more within 50 km; the five largest:

1. 6.6 146 km ESE of Akutan, Alaska · 34 km S of this epicentre Apr 1, 1946
2. 6.2 Unimak Island region, Alaska · 9 km SW of this epicentre Oct 14, 1933
3. 6.2 102 km SSW of False Pass, Alaska · 20 km NNW of this epicentre Aug 20, 1939
4. 6.2 136 km SE of Akutan, Alaska · 47 km SSW of this epicentre Apr 1, 1946
5. 6.2 136 km S of False Pass, Alaska · 23 km SSE of this epicentre Apr 2, 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 53.8420, -163.8630. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.4 83 km S of False Pass, Alaska 11:11 UTC
2. 2.4 119 km S of False Pass, Alaska 23:42 UTC
3. 3.1 122 km SSW of False Pass, Alaska 18:38 UTC
4. 2.7 123 km SE of Akutan, Alaska 06:32 UTC
5. 3.3 110 km ESE of Akutan, Alaska 10:50 UTC
6. 2.6 101 km SSW of False Pass, Alaska 19:32 UTC
7. 3.3 100 km E of Akutan, Alaska 10:00 UTC
8. 3.0 113 km ESE of Akutan, Alaska 05:10 UTC
9. 2.4 146 km S of False Pass, Alaska 23:32 UTC
10. 2.8 151 km S of False Pass, Alaska 21:47 UTC
11. 2.5 151 km S of False Pass, Alaska 21:11 UTC
12. 3.8 150 km S of False Pass, Alaska 20:08 UTC
13. 2.3 102 km ESE of Akutan, Alaska 18:44 UTC
14. 2.8 149 km S of False Pass, Alaska 17:28 UTC
15. 2.7 147 km S of False Pass, Alaska 14:53 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 20:17 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.