98 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 246 km (153 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 1.9 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.4 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 89× the energy of this one
2. Mineral, Virginia 2011 M 5.8 4× the energy of this one
3. Magna, Utah 2020 M 5.7 2.8× the energy of this one
4. This earthquake M 5.4 about 1.9 kilotons of TNT
5. Around the size people start to feel M 3.0 this one released 4,000× 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 2024-12-08 — about 22 times the energy of this one.

Before 2016, the USGS record lists 79 earthquakes of M5 or more within 50 km; the five largest:

1. 7.1 60 km SW of Adak, Alaska · 46 km N of this epicentre Mar 12, 1957
2. 7.1 75 km S of Adak, Alaska · 37 km ENE of this epicentre Mar 14, 1957
3. 7.0 69 km SW of Adak, Alaska · 38 km N of this epicentre May 2, 1971
4. 6.9 61 km SSW of Adak, Alaska · 40 km NE of this epicentre Feb 7, 1971
5. 6.8 90 km SSW of Adak, Alaska · 17 km E of this epicentre Mar 11, 1957

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 51.0688, -177.2241. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.5 110 km SSW of Adak, Alaska 01:07 UTC
2. 3.1 102 km SSW of Adak, Alaska 01:07 UTC
3. 2.6 116 km SSW of Adak, Alaska 01:01 UTC
4. 2.2 116 km SSW of Adak, Alaska 01:01 UTC
5. 2.2 115 km SSW of Adak, Alaska 01:00 UTC
6. 3.6 109 km SSW of Adak, Alaska 00:59 UTC
7. 2.7 122 km SSW of Adak, Alaska 00:59 UTC
8. 4.0 130 km SSW of Adak, Alaska 00:55 UTC
9. 2.7 116 km SSW of Adak, Alaska 00:52 UTC
10. 2.5 132 km SSW of Adak, Alaska 00:51 UTC
11. 2.3 121 km SSW of Adak, Alaska 00:51 UTC
12. 3.2 124 km SSW of Adak, Alaska 00:49 UTC
13. 3.0 125 km SSW of Adak, Alaska 00:48 UTC
14. 3.5 124 km SSW of Adak, Alaska 00:47 UTC
15. 3.2 117 km SSW of Adak, Alaska 00:46 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 09:43 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.