133 km SE of Perryville, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 55 km (34 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 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 89,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 4,000× the energy of this one
3. Magna, Utah 2020 M 5.7 2,800× the energy of this one
4. This earthquake M 3.4 about 1.9 tons of TNT
5. Around the size people start to feel M 3.0 this one released 4× 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 8.2 on 2021-07-29 — about 16,000,000 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

1. 8.2 1938 Semidi Islands, Alaska Earthquake · 33 km NW of this epicentre Nov 10, 1938
2. 6.9 105 km ESE of Perryville, Alaska · 46 km N of this epicentre Nov 17, 1938
3. 6.2 143 km SE of Perryville, Alaska · 11 km SSE of this epicentre Mar 25, 1927
4. 6.0 98 km ESE of Perryville, Alaska · 48 km N of this epicentre Jan 2, 1985
5. 5.9 182 km SE of Perryville, Alaska · 49 km SE of this epicentre Dec 23, 1938

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 54.9977, -157.7787. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.4 114 km SSE of Perryville, Alaska 10:55 UTC
2. 3.4 86 km SE of Perryville, Alaska 02:12 UTC
3. 2.5 120 km ESE of Perryville, Alaska 23:28 UTC
4. 3.9 125 km SE of Perryville, Alaska 22:38 UTC
5. 3.4 142 km SE of Perryville, Alaska 13:00 UTC
6. 2.3 124 km SE of Perryville, Alaska 06:53 UTC
7. 2.6 130 km SE of Perryville, Alaska 01:16 UTC
8. 2.7 136 km SSE of Perryville, Alaska 13:33 UTC
9. 3.0 121 km SE of Perryville, Alaska 19:20 UTC
10. 2.3 109 km SE of Perryville, Alaska 03:49 UTC
11. 2.1 100 km SE of Perryville, Alaska 06:31 UTC
12. 3.3 129 km SE of Perryville, Alaska 08:57 UTC
13. 2.9 116 km SE of Perryville, Alaska 00:01 UTC
14. 2.6 128 km SE of Perryville, Alaska 04:17 UTC
15. 2.4 117 km SE of Perryville, Alaska 19:15 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 17:23 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.