136 km SE of Perryville, Alaska

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

How big was it?

This earthquake released about 3.8 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.6 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 45,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 2,000× the energy of this one
3. Magna, Utah 2020 M 5.7 1,400× the energy of this one
4. This earthquake M 3.6 about 3.8 tons of TNT
5. Around the size people start to feel M 3.0 this one released 7.9× 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.

Where

Epicentre 55.1438, -157.4588. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.2 125 km SE of Perryville, Alaska 07:45 UTC
2. 2.0 124 km SE of Perryville, Alaska 05:17 UTC
3. 2.4 130 km SE of Perryville, Alaska 04:28 UTC
4. 2.4 162 km SE of Chignik, Alaska 12:56 UTC
5. 3.0 161 km SE of Perryville, Alaska 12:18 UTC
6. 2.5 165 km SE of Perryville, Alaska 11:58 UTC
7. 3.0 143 km SE of Perryville, Alaska 11:21 UTC
8. 2.5 124 km SE of Perryville, Alaska 09:08 UTC
9. 2.3 109 km SE of Perryville, Alaska 08:44 UTC
10. 2.3 113 km SE of Perryville, Alaska 04:08 UTC
11. 2.1 138 km SSE of Chignik, Alaska 23:45 UTC
12. 2.6 143 km SE of Perryville, Alaska 23:35 UTC
13. 2.6 125 km SE of Perryville, Alaska 22:25 UTC
14. 2.8 127 km SE of Perryville, Alaska 21:56 UTC
15. 3.9 131 km SE of Perryville, Alaska 18:44 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:07 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 8.2 on 2021-07-29 — it released about 7,900,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.