113 km E of Chignik, 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 250,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
4. This earthquake M 3.1 about 1,300 lb of TNT
5. Around the size people start to feel M 3.0 this one released 1.4× 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.

Where

Epicentre 56.2980, -156.5640. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.3 129 km E of Chignik, Alaska 20:31 UTC
2. 2.8 112 km E of Chignik, Alaska 19:59 UTC
3. 2.1 109 km E of Chignik, Alaska 20:19 UTC
4. 4.0 119 km E of Chignik, Alaska 14:32 UTC
5. 2.0 90 km E of Chignik, Alaska 00:36 UTC
6. 2.0 102 km ENE of Chignik, Alaska 18:55 UTC
7. 2.6 115 km E of Chignik, Alaska 15:25 UTC
8. 2.8 118 km E of Chignik, Alaska 21:38 UTC
9. 2.8 128 km E of Chignik, Alaska 17:06 UTC
10. 2.3 113 km SSE of Ugashik, Alaska 22:02 UTC
11. 2.9 119 km SSE of Ugashik, Alaska 20:19 UTC
12. 2.2 89 km E of Chignik, Alaska 08:13 UTC
13. 2.2 114 km E of Chignik, Alaska 00:13 UTC
14. 2.1 123 km E of Chignik, Alaska 10:53 UTC
15. 1.9 81 km E of Chignik, Alaska 13:38 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 10:23 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 2021-10-11 — it released about 500,000 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.