122 km SE of Chignik, Alaska

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

How big was it?

This earthquake released about 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 11,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 500× the energy of this one
3. Magna, Utah 2020 M 5.7 350× the energy of this one
4. This earthquake M 4.0 about 15 tons of TNT
5. Around the size people start to feel M 3.0 this one released 32× 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 55.4330, -157.1926. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 4.4 100 km SE of Chignik, Alaska 14:37 UTC
2. 1.9 94 km SSE of Chignik, Alaska 03:18 UTC
3. 3.0 128 km SE of Perryville, Alaska 02:56 UTC
4. 2.3 145 km SE of Perryville, Alaska 19:52 UTC
5. 2.6 147 km SE of Perryville, Alaska 17:52 UTC
6. 2.4 128 km SE of Perryville, Alaska 15:43 UTC
7. 2.2 146 km SE of Perryville, Alaska 15:23 UTC
8. 3.5 141 km SE of Perryville, Alaska 08:25 UTC
9. 2.2 150 km SE of Chignik, Alaska 08:56 UTC
10. 2.5 131 km SE of Perryville, Alaska 17:24 UTC
11. 3.1 155 km SSE of Chignik, Alaska 11:34 UTC
12. 2.2 107 km SSE of Chignik, Alaska 03:57 UTC
13. 2.0 115 km SE of Perryville, Alaska 23:27 UTC
14. 2.2 93 km SE of Chignik, Alaska 07:38 UTC
15. 2.3 160 km SE of Chignik, Alaska 19:03 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 18:04 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 6.9 on 2021-08-14 — it released about 22,000 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.