138 km SW of Nikolski, Alaska

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

How big was it?

This earthquake released about 21 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 7,900× the energy of this one
2. Mineral, Virginia 2011 M 5.8 350× the energy of this one
3. Magna, Utah 2020 M 5.7 250× the energy of this one
4. This earthquake M 4.1 about 21 tons of TNT
5. Around the size people start to feel M 3.0 this one released 45× 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 52.2486, -170.5541. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 126 km SW of Nikolski, Alaska 11:56 UTC
2. 2.9 141 km SW of Nikolski, Alaska 09:06 UTC
3. 2.0 116 km SW of Nikolski, Alaska 12:42 UTC
4. 2.9 Fox Islands, Aleutian Islands, Alaska 17:53 UTC
5. 3.3 185 km SW of Nikolski, Alaska 18:23 UTC
6. 3.6 181 km SW of Nikolski, Alaska 00:46 UTC
7. 3.5 157 km SW of Nikolski, Alaska 10:16 UTC
8. 3.0 100 km WSW of Nikolski, Alaska 20:35 UTC
9. 3.0 161 km WSW of Nikolski, Alaska 18:24 UTC
10. 2.8 Fox Islands, Aleutian Islands, Alaska 06:42 UTC
11. 3.2 119 km WSW of Nikolski, Alaska 10:13 UTC
12. 2.8 127 km SW of Nikolski, Alaska 06:19 UTC
13. 1.9 Fox Islands, Aleutian Islands, Alaska 18:24 UTC
14. 3.4 145 km WSW of Nikolski, Alaska 23:23 UTC
15. 2.6 142 km WSW of Nikolski, Alaska 00:42 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:10 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 5.8 on 2019-10-26 — it released about 350 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.