69 km SE of Old Harbor, 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 (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 56 earthquakes of M5 or more within 50 km; the five largest:

1. 6.9 47 km S of Old Harbor, Alaska · 46 km W of this epicentre Jan 10, 2001
2. 6.6 88 km SSE of Old Harbor, Alaska · 39 km SSW of this epicentre Dec 21, 1917
3. 6.6 94 km SSE of Old Harbor, Alaska · 38 km SSW of this epicentre Apr 12, 1978
4. 6.5 85 km SSE of Old Harbor, Alaska · 44 km SW of this epicentre Mar 30, 1964
5. 6.3 98 km SE of Old Harbor, Alaska · 31 km SSE of this epicentre Apr 12, 1964

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 56.7493, -152.5231. Map © OpenStreetMap contributors.

Nearby places

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

1. 2.6 117 km SE of Old Harbor, Alaska 23:45 UTC
2. 2.8 115 km SE of Old Harbor, Alaska 23:17 UTC
3. 2.8 116 km SE of Old Harbor, Alaska 23:06 UTC
4. 2.5 112 km SE of Old Harbor, Alaska 23:05 UTC
5. 3.4 117 km SE of Old Harbor, Alaska 22:57 UTC
6. 4.7 116 km SE of Old Harbor, Alaska 22:52 UTC
7. 2.7 107 km SE of Old Harbor, Alaska 18:35 UTC
8. 3.0 109 km SSE of Old Harbor, Alaska 11:10 UTC
9. 3.1 117 km SE of Old Harbor, Alaska 10:39 UTC
10. 2.5 27 km SE of Old Harbor, Alaska 20:45 UTC
11. 1.8 25 km SE of Old Harbor, Alaska 10:58 UTC
12. 1.6 42 km SSE of Old Harbor, Alaska 22:54 UTC
13. 1.5 40 km ESE of Old Harbor, Alaska 22:56 UTC
14. 1.8 48 km SE of Old Harbor, Alaska 22:36 UTC
15. 2.1 51 km SE of Old Harbor, Alaska 22:29 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:06 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.