117 km SSE of Ugashik, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 130,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 5,600× the energy of this one
3. Magna, Utah 2020 M 5.7 4,000× the energy of this one
4. This earthquake M 3.3 about 1.3 tons of TNT
5. Around the size people start to feel M 3.0 this one released 2.8× 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 56.6084, -156.3936. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.9 90 km SSE of Ugashik, Alaska 09:14 UTC
2. 2.1 126 km WSW of Akhiok, Alaska 05:11 UTC
3. 1.8 119 km SSE of Ugashik, Alaska 16:00 UTC
4. 2.2 104 km W of Akhiok, Alaska 13:54 UTC
5. 1.5 110 km W of Akhiok, Alaska 11:18 UTC
6. 1.7 105 km SSE of Ugashik, Alaska 00:59 UTC
7. 2.6 128 km E of Chignik, Alaska 05:49 UTC
8. 2.2 130 km WSW of Akhiok, Alaska 10:08 UTC
9. 1.6 105 km W of Akhiok, Alaska 19:56 UTC
10. 1.7 119 km E of Chignik, Alaska 04:22 UTC
11. 2.1 74 km SSE of Ugashik, Alaska 10:03 UTC
12. 1.9 93 km SSE of Ugashik, Alaska 08:32 UTC
13. 1.5 89 km SE of Ugashik, Alaska 21:54 UTC
14. 1.5 89 km SE of Ugashik, Alaska 13:51 UTC
15. 1.5 106 km SE of Ugashik, Alaska 16:46 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:53 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 250,000 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.