84 km SSE of Ugashik, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 5.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 32,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 1,400× the energy of this one
3. Magna, Utah 2020 M 5.7 1,000× the energy of this one
4. This earthquake M 3.7 about 5.4 tons of TNT
5. Around the size people start to feel M 3.0 this one released 11× 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 56.7976, -156.9210. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.3 101 km SSE of Ugashik, Alaska 06:50 UTC
2. 1.9 65 km SSE of Ugashik, Alaska 17:13 UTC
3. 3.3 56 km SE of Ugashik, Alaska 10:33 UTC
4. 2.3 49 km SE of Ugashik, Alaska 10:30 UTC
5. 2.5 51 km SE of Ugashik, Alaska 07:47 UTC
6. 3.1 60 km SE of Ugashik, Alaska 07:34 UTC
7. 1.9 Alaska Peninsula 19:33 UTC
8. 1.8 87 km ENE of Chignik, Alaska 11:50 UTC
9. 2.3 115 km SSE of Ugashik, Alaska 20:33 UTC
10. 1.9 61 km SSE of Ugashik, Alaska 19:14 UTC
11. 1.6 74 km ESE of Port Heiden, Alaska 18:18 UTC
12. 2.2 87 km ENE of Chignik, Alaska 23:26 UTC
13. 2.8 82 km ENE of Chignik, Alaska 12:35 UTC
14. 1.7 70 km ENE of Chignik, Alaska 12:58 UTC
15. 2.0 84 km SSE of Ugashik, Alaska 10:09 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 12:33 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 4.5 on 2016-02-14 — it released about 16 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.