220 km SSW 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 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 11,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 500× the energy of this one
3. Magna, Utah 2020 M 5.7 350× the energy of this one
4. This earthquake M 4.0 about 15 tons of TNT
5. Around the size people start to feel M 3.0 this one released 32× 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 51.0904, -170.0121. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.9 187 km SSW of Nikolski, Alaska 05:03 UTC
2. 3.0 232 km SSW of Nikolski, Alaska 13:30 UTC
3. 3.1 229 km SSW of Nikolski, Alaska 04:34 UTC
4. 3.0 243 km SSW of Nikolski, Alaska 07:51 UTC
5. 3.1 205 km SSW of Nikolski, Alaska 17:56 UTC
6. 3.8 185 km SSW of Nikolski, Alaska 12:32 UTC
7. 3.2 217 km SSW of Nikolski, Alaska 21:58 UTC
8. 2.7 184 km SSW of Nikolski, Alaska 07:47 UTC
9. 2.9 191 km SSW of Nikolski, Alaska 13:00 UTC
10. 2.8 190 km SSW of Nikolski, Alaska 11:34 UTC
11. 2.9 201 km SSW of Nikolski, Alaska 08:52 UTC
12. 3.4 206 km SSW of Nikolski, Alaska 22:13 UTC
13. 3.8 202 km SSW of Nikolski, Alaska 16:57 UTC
14. 3.8 195 km SSW of Nikolski, Alaska 13:20 UTC
15. 3.5 206 km SSW of Nikolski, Alaska 17:53 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 18:30 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 4.6 on 2017-11-15 — it released about 7.9 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.