199 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.

At this magnitude and depth, people at rest would likely notice it out to about 110 km (68 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 43 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 4,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 180× the energy of this one
3. Magna, Utah 2020 M 5.7 130× the energy of this one
4. This earthquake M 4.3 about 43 tons of TNT
5. Around the size people start to feel M 3.0 this one released 89× 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.

For this area

The largest earthquake within 50 km since 2016 was M 5.9 on 2018-08-25 — about 250 times the energy of this one.

Before 2016, the USGS record lists 68 earthquakes of M5 or more within 50 km; the five largest:

1. 7.3 Fox Islands, Aleutian Islands, Alaska · 37 km WNW of this epicentre Jun 24, 2011
2. 6.9 170 km E of Atka, Alaska · 35 km NW of this epicentre Sep 2, 2011
3. 6.2 179 km SW of Nikolski, Alaska · 47 km ESE of this epicentre Jun 4, 1956
4. 6.1 185 km ESE of Atka, Alaska · 20 km SW of this epicentre Dec 6, 1930
5. 6.1 207 km ESE of Atka, Alaska · 34 km S of this epicentre Mar 13, 1957

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 51.9619, -171.3179. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.3 193 km ESE of Atka, Alaska 16:43 UTC
2. 2.9 206 km ESE of Atka, Alaska 12:05 UTC
3. 3.2 210 km ESE of Atka, Alaska 07:34 UTC
4. 3.1 181 km ESE of Atka, Alaska 20:34 UTC
5. 4.5 184 km E of Atka, Alaska 09:24 UTC
6. 2.2 170 km WSW of Nikolski, Alaska 23:11 UTC
7. 3.2 218 km SW of Nikolski, Alaska 20:26 UTC
8. 3.7 198 km SW of Nikolski, Alaska 15:34 UTC
9. 3.3 171 km E of Atka, Alaska 21:53 UTC
10. 3.4 159 km WSW of Nikolski, Alaska 06:44 UTC
11. 3.4 179 km ESE of Atka, Alaska 09:11 UTC
12. 3.0 186 km SW of Nikolski, Alaska 22:52 UTC
13. 3.1 174 km E of Atka, Alaska 02:01 UTC
14. 3.6 195 km E of Atka, Alaska 08:23 UTC
15. 3.1 197 km SW of Nikolski, Alaska 04:59 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 10:35 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

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.