121 km S of Unalaska, 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 2.7 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 63,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 2,800× the energy of this one
3. Magna, Utah 2020 M 5.7 2,000× the energy of this one
4. This earthquake M 3.5 about 2.7 tons of TNT
5. Around the size people start to feel M 3.0 this one released 5.6× 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 52.7887, -166.7517. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.9 148 km S of Unalaska, Alaska 02:20 UTC
2. 2.1 99 km S of Unalaska, Alaska 05:17 UTC
3. 2.4 130 km S of Unalaska, Alaska 00:22 UTC
4. 2.3 136 km S of Unalaska, Alaska 18:27 UTC
5. 2.2 139 km S of Unalaska, Alaska 04:13 UTC
6. 1.9 132 km S of Unalaska, Alaska 01:32 UTC
7. 2.3 134 km S of Unalaska, Alaska 16:00 UTC
8. 1.7 129 km S of Unalaska, Alaska 15:29 UTC
9. 2.5 128 km S of Unalaska, Alaska 03:15 UTC
10. 1.9 119 km S of Unalaska, Alaska 07:27 UTC
11. 2.1 124 km ESE of Nikolski, Alaska 04:39 UTC
12. 2.0 Fox Islands, Aleutian Islands, Alaska 14:48 UTC
13. 2.3 125 km S of Unalaska, Alaska 14:33 UTC
14. 2.1 129 km ESE of Nikolski, Alaska 12:53 UTC
15. 2.2 132 km ESE of Nikolski, Alaska 12:44 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 17:26 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 5.4 on 2016-07-26 — it released about 710 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.