49 km SW 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 139 km (86 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 240 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.8 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 710× the energy of this one
2. Mineral, Virginia 2011 M 5.8 32× the energy of this one
3. Magna, Utah 2020 M 5.7 22× the energy of this one
4. This earthquake M 4.8 about 240 tons of TNT
5. Around the size people start to feel M 3.0 this one released 500× 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 (31 mi) since our catalogue begins in 2016. No other earthquake of M4 or more has been recorded this close in that time.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

1. 6.5 79 km SW of False Pass, Alaska · 32 km SSW of this epicentre Nov 19, 1993
2. 5.9 27 km W of False Pass, Alaska · 36 km NNE of this epicentre Oct 1, 1951
3. 5.8 85 km SW of False Pass, Alaska · 39 km SSW of this epicentre Jan 3, 1998
4. 5.6 87 km SSW of False Pass, Alaska · 42 km SSW of this epicentre Dec 27, 1983
5. 5.6 52 km SSW of False Pass, Alaska · 12 km SE of this epicentre Jun 4, 2004

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 54.5511, -163.9662. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 41 km W of False Pass, Alaska 12:00 UTC
2. 1.6 84 km SW of False Pass, Alaska 08:18 UTC
3. 2.1 96 km SSW of False Pass, Alaska 19:04 UTC
4. 3.0 95 km SW of False Pass, Alaska 18:59 UTC
5. 2.0 27 km SSW of False Pass, Alaska 09:08 UTC
6. 1.7 4 km SSW of False Pass, Alaska 17:55 UTC
7. 2.9 6 km SW of False Pass, Alaska 15:03 UTC
8. 2.1 31 km SSW of False Pass, Alaska 00:50 UTC
9. 2.0 90 km SW of False Pass, Alaska 09:00 UTC
10. 2.1 86 km SSW of False Pass, Alaska 09:05 UTC
11. 2.2 81 km SW of False Pass, Alaska 23:22 UTC
12. 2.1 90 km SSW of False Pass, Alaska 08:29 UTC
13. 2.8 60 km SSW of False Pass, Alaska 02:44 UTC
14. 3.0 89 km SSW of False Pass, Alaska 23:49 UTC
15. 2.8 20 km SSW of False Pass, Alaska 16:14 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:35 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.