163 km SSE of False Pass, Alaska

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

At this magnitude and depth, people at rest would likely notice it out to about 13 km (8 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 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 4.9 on 2016-10-28 — about 2,800 times the energy of this one.

Before 2016, the USGS record lists 21 earthquakes of M5 or more within 50 km; the five largest:

1. 8.6 The 1946 Unimak Island, Alaska Earthquake · 10 km WNW of this epicentre Apr 1, 1946
2. 6.2 172 km SSE of False Pass, Alaska · 15 km SW of this epicentre Apr 2, 1946
3. 6.1 166 km S of False Pass, Alaska · 29 km WSW of this epicentre Oct 14, 1929
4. 6.0 155 km S of False Pass, Alaska · 50 km W of this epicentre Apr 3, 1946
5. 6.0 137 km S of False Pass, Alaska · 42 km WNW of this epicentre May 22, 1988

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 53.4453, -162.7094. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.9 131 km SSE of False Pass, Alaska 16:54 UTC
2. 3.2 178 km SSE of False Pass, Alaska 18:11 UTC
3. 2.4 118 km SSE of False Pass, Alaska 07:57 UTC
4. 2.7 198 km SSE of False Pass, Alaska 08:11 UTC
5. 3.8 209 km SSE of False Pass, Alaska 14:38 UTC
6. 2.4 166 km S of False Pass, Alaska 03:50 UTC
7. 2.5 south of Alaska 21:27 UTC
8. 2.1 133 km SSE of False Pass, Alaska 15:05 UTC
9. 2.8 146 km SSE of False Pass, Alaska 13:56 UTC
10. 2.2 123 km SSE of False Pass, Alaska 10:35 UTC
11. 2.5 Unimak Island region, Alaska 17:54 UTC
12. 1.9 139 km SSE of False Pass, Alaska 10:01 UTC
13. 3.2 192 km SSE of False Pass, Alaska 14:51 UTC
14. 2.9 south of Alaska 12:10 UTC
15. 3.1 117 km SSE of False Pass, Alaska 22:33 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 03:01 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.