139 km ESE 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 52.5658, -166.8961. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.9 102 km E of Nikolski, Alaska 04:55 UTC
2. 2.2 127 km S of Unalaska, Alaska 19:17 UTC
3. 2.0 111 km SSW of Unalaska, Alaska 12:52 UTC
4. 2.1 113 km SSW of Unalaska, Alaska 12:33 UTC
5. 2.0 138 km S of Unalaska, Alaska 15:08 UTC
6. 1.8 138 km S of Unalaska, Alaska 11:14 UTC
7. 2.6 131 km S of Unalaska, Alaska 10:09 UTC
8. 2.1 111 km S of Unalaska, Alaska 16:59 UTC
9. 2.9 122 km S of Unalaska, Alaska 15:22 UTC
10. 2.3 133 km ESE of Nikolski, Alaska 19:13 UTC
11. 2.6 143 km S of Unalaska, Alaska 15:44 UTC
12. 2.8 127 km S of Unalaska, Alaska 13:19 UTC
13. 2.7 137 km S of Unalaska, Alaska 07:32 UTC
14. 2.9 128 km S of Unalaska, Alaska 17:03 UTC
15. 3.4 122 km S of Unalaska, Alaska 12:23 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:56 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 5.9 on 2017-05-24 — 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.