180 km SW of Nikolski, Alaska

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 240 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 63,000× the energy of this one
2. Magna, Utah 2020 M 5.7 45,000× the energy of this one
3. Around the size people start to feel M 3.0 4× the energy of this one
4. This earthquake M 2.6 about 240 lb of TNT

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 5.2 on 2017-05-19 — about 7,900 times the energy of this one.

Before 2016, the USGS record lists 75 earthquakes of M5 or more within 50 km; the five largest:

1. 6.2 179 km SW of Nikolski, Alaska · 33 km SE of this epicentre Jun 4, 1956
2. 6.2 Fox Islands, Aleutian Islands, Alaska · 46 km SSE of this epicentre Mar 10, 1957
3. 6.1 185 km ESE of Atka, Alaska · 40 km WSW of this epicentre Dec 6, 1930
4. 6.1 207 km ESE of Atka, Alaska · 43 km SSW of this epicentre Mar 13, 1957
5. 6.1 Fox Islands, Aleutian Islands, Alaska · 25 km SSE of this epicentre Jan 11, 1961

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 52.0039, -171.0257. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.9 184 km WSW of Nikolski, Alaska 07:43 UTC
2. 2.7 148 km WSW of Nikolski, Alaska 01:50 UTC
3. 3.0 178 km WSW of Nikolski, Alaska 15:00 UTC
4. 3.0 142 km SW of Nikolski, Alaska 03:30 UTC
5. 2.8 185 km ESE of Atka, Alaska 03:04 UTC
6. 3.7 199 km E of Atka, Alaska 22:20 UTC
7. 2.8 150 km SW of Nikolski, Alaska 18:24 UTC
8. 2.9 178 km WSW of Nikolski, Alaska 10:24 UTC
9. 3.9 179 km WSW of Nikolski, Alaska 14:48 UTC
10. 3.0 192 km ESE of Atka, Alaska 06:41 UTC
11. 3.7 195 km ESE of Atka, Alaska 17:26 UTC
12. 2.5 150 km WSW of Nikolski, Alaska 08:41 UTC
13. 2.5 145 km WSW of Nikolski, Alaska 05:09 UTC
14. 3.7 174 km WSW of Nikolski, Alaska 00:09 UTC
15. 3.8 176 km SW of Nikolski, Alaska 08:16 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:52 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.