122 km SSW of Adak, Alaska

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

At this magnitude and depth, people at rest would likely notice it out to about 218 km (135 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 950 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.2 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 180× the energy of this one
2. Mineral, Virginia 2011 M 5.8 7.9× the energy of this one
3. Magna, Utah 2020 M 5.7 5.6× the energy of this one
4. This earthquake M 5.2 about 950 tons of TNT
5. Around the size people start to feel M 3.0 this one released 2,000× 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 6.3 on 2024-12-09 — about 45 times the energy of this one.

Before 2016, the USGS record lists 42 earthquakes of M5 or more within 50 km; the five largest:

1. 6.8 90 km SSW of Adak, Alaska · 33 km NNE of this epicentre Mar 11, 1957
2. 6.6 85 km SSW of Adak, Alaska · 38 km NNE of this epicentre Jul 5, 1929
3. 6.4 146 km S of Adak, Alaska · 41 km SE of this epicentre Mar 10, 1957
4. 6.4 76 km SSW of Adak, Alaska · 50 km N of this epicentre Jul 23, 1957
5. 6.0 130 km SSW of Adak, Alaska · 17 km W of this epicentre Mar 20, 1927

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 50.8375, -177.2197. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.9 123 km SSW of Adak, Alaska 03:07 UTC
2. 3.0 116 km SSW of Adak, Alaska 03:05 UTC
3. 2.2 115 km SSW of Adak, Alaska 03:01 UTC
4. 3.4 123 km SSW of Adak, Alaska 02:57 UTC
5. 2.9 119 km SSW of Adak, Alaska 02:50 UTC
6. 2.2 90 km SSW of Adak, Alaska 02:48 UTC
7. 2.9 113 km SSW of Adak, Alaska 02:47 UTC
8. 2.3 114 km SSW of Adak, Alaska 02:30 UTC
9. 2.8 118 km SSW of Adak, Alaska 02:25 UTC
10. 2.1 110 km SW of Adak, Alaska 02:23 UTC
11. 2.5 111 km SSW of Adak, Alaska 02:17 UTC
12. 2.7 105 km SSW of Adak, Alaska 02:12 UTC
13. 3.0 121 km SSW of Adak, Alaska 02:09 UTC
14. 2.1 108 km SSW of Adak, Alaska 02:08 UTC
15. 3.4 123 km SSW of Adak, Alaska 01:59 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:32 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.