253 km SE of Akutan, 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 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 180,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
4. This earthquake M 3.2 about 1,900 lb of TNT
5. Around the size people start to feel M 3.0 this one released 2× 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 52.5662, -163.0120. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.2 228 km S of False Pass, Alaska 05:17 UTC
2. 2.7 209 km SE of Akutan, Alaska 16:56 UTC
3. 3.0 210 km S of False Pass, Alaska 23:55 UTC
4. 3.0 269 km S of False Pass, Alaska 03:34 UTC
5. 2.5 221 km S of False Pass, Alaska 14:10 UTC
6. 2.7 288 km SE of Akutan, Alaska 05:54 UTC
7. 2.7 219 km SE of Akutan, Alaska 16:14 UTC
8. 2.6 215 km SE of Akutan, Alaska 08:36 UTC
9. 2.9 233 km S of False Pass, Alaska 03:34 UTC
10. 3.2 239 km S of False Pass, Alaska 07:06 UTC
11. 2.8 221 km S of False Pass, Alaska 11:03 UTC
12. 2.8 232 km SSE of False Pass, Alaska 13:56 UTC
13. 2.2 234 km SE of Akutan, Alaska 23:22 UTC
14. 3.0 252 km SE of Akutan, Alaska 23:21 UTC
15. 2.5 227 km SE of Akutan, Alaska 20:32 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 14:19 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 5.0 on 2016-10-01 — it released about 500 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.