79 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 13 km (8 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 4.5 on 2018-10-28 — about 1,400 times the energy of this one.

Before 2016, the USGS record lists 21 earthquakes of M5 or more within 50 km; the five largest:

1. 6.5 47 km SE of False Pass, Alaska · 49 km NNE of this epicentre Feb 26, 1929
2. 6.5 88 km SE of False Pass, Alaska · 38 km E of this epicentre Jun 21, 1987
3. 6.0 96 km SSW of False Pass, Alaska · 41 km WSW of this epicentre May 29, 1973
4. 5.7 88 km SE of False Pass, Alaska · 39 km E of this epicentre Apr 26, 1965
5. 5.7 99 km SE of False Pass, Alaska · 41 km E of this epicentre Nov 6, 2011

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 54.1568, -163.1803. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 113 km S of False Pass, Alaska 16:43 UTC
2. 2.5 101 km S of False Pass, Alaska 01:20 UTC
3. 3.5 98 km S of False Pass, Alaska 17:31 UTC
4. 2.6 104 km S of False Pass, Alaska 14:36 UTC
5. 2.5 87 km S of False Pass, Alaska 02:35 UTC
6. 2.9 102 km S of False Pass, Alaska 23:06 UTC
7. 2.0 68 km S of False Pass, Alaska 21:41 UTC
8. 3.8 120 km S of False Pass, Alaska 07:47 UTC
9. 3.5 102 km S of False Pass, Alaska 18:12 UTC
10. 2.6 84 km S of False Pass, Alaska 23:43 UTC
11. 2.3 87 km S of False Pass, Alaska 17:01 UTC
12. 2.4 84 km S of False Pass, Alaska 06:31 UTC
13. 2.1 68 km SE of False Pass, Alaska 22:26 UTC
14. 2.4 89 km S of False Pass, Alaska 19:41 UTC
15. 2.3 88 km S of False Pass, Alaska 14:20 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 05:56 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.