92 km S of False Pass, Alaska

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 103 km (64 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 30 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 5,600× the energy of this one
2. Mineral, Virginia 2011 M 5.8 250× the energy of this one
3. Magna, Utah 2020 M 5.7 180× the energy of this one
4. This earthquake M 4.2 about 30 tons of TNT
5. Around the size people start to feel M 3.0 this one released 63× 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.

For this area

The largest earthquake within 50 km since 2016 was M 5.9 on 2016-10-27 — about 350 times the energy of this one.

Before 2016, the USGS record lists 32 earthquakes of M5 or more within 50 km; the five largest:

1. 6.2 Unimak Island region, Alaska · 48 km WSW of this epicentre Oct 14, 1933
2. 6.2 102 km SSW of False Pass, Alaska · 43 km W of this epicentre Aug 20, 1939
3. 6.2 136 km S of False Pass, Alaska · 50 km SW of this epicentre Apr 2, 1946
4. 6.0 129 km S of False Pass, Alaska · 37 km S of this epicentre Jan 14, 1961
5. 6.0 96 km SSW of False Pass, Alaska · 27 km W of this epicentre May 29, 1973

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 54.0216, -163.3435. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.6 103 km S of False Pass, Alaska 18:57 UTC
2. 2.6 107 km S of False Pass, Alaska 18:50 UTC
3. 2.8 123 km SSE of False Pass, Alaska 14:24 UTC
4. 2.7 100 km SSE of False Pass, Alaska 10:19 UTC
5. 2.8 132 km SSE of False Pass, Alaska 07:20 UTC
6. 2.5 94 km SSE of False Pass, Alaska 05:31 UTC
7. 2.8 131 km SSE of False Pass, Alaska 01:15 UTC
8. 2.9 128 km SSE of False Pass, Alaska 09:57 UTC
9. 2.9 135 km SSE of False Pass, Alaska 00:30 UTC
10. 2.4 109 km SSE of False Pass, Alaska 02:54 UTC
11. 2.4 107 km S of False Pass, Alaska 23:31 UTC
12. 2.1 58 km SSE of False Pass, Alaska 17:58 UTC
13. 2.2 48 km SSE of False Pass, Alaska 17:02 UTC
14. 4.8 127 km S of False Pass, Alaska 14:46 UTC
15. 3.5 123 km S of False Pass, Alaska 06:04 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 01:08 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.