150 km SW of Nikolski, 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 5.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 32,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 1,400× the energy of this one
3. Magna, Utah 2020 M 5.7 1,000× the energy of this one
4. This earthquake M 3.7 about 5.4 tons of TNT
5. Around the size people start to feel M 3.0 this one released 11× 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 52.0121, -170.4799. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.8 114 km SW of Nikolski, Alaska 07:00 UTC
2. 2.2 178 km SW of Nikolski, Alaska 17:28 UTC
3. 3.8 106 km SW of Nikolski, Alaska 20:29 UTC
4. 3.6 115 km SW of Nikolski, Alaska 15:05 UTC
5. 3.8 154 km SW of Nikolski, Alaska 01:10 UTC
6. 4.9 128 km WSW of Nikolski, Alaska 16:47 UTC
7. 2.5 136 km SW of Nikolski, Alaska 15:10 UTC
8. 3.4 134 km SW of Nikolski, Alaska 18:54 UTC
9. 3.6 164 km SW of Nikolski, Alaska 20:55 UTC
10. 3.6 136 km SW of Nikolski, Alaska 01:40 UTC
11. 3.1 135 km SW of Nikolski, Alaska 08:23 UTC
12. 3.5 160 km SW of Nikolski, Alaska 23:01 UTC
13. 3.3 153 km SW of Nikolski, Alaska 17:38 UTC
14. 2.2 113 km SW of Nikolski, Alaska 11:15 UTC
15. 3.1 132 km SW of Nikolski, Alaska 00:01 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:17 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 1,400 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.