155 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 23 km (14 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 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
3. Around the size people start to feel M 3.0 2.8× the energy of this one
4. This earthquake M 2.7 about 340 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 4.4 on 2021-07-22 — about 350 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

1. 8.6 The 1946 Unimak Island, Alaska Earthquake · 40 km WSW of this epicentre Apr 1, 1946
2. 5.9 146 km SSE of King Cove, Alaska · 49 km ENE of this epicentre Apr 21, 1971
3. 5.8 112 km SE of False Pass, Alaska · 46 km N of this epicentre Feb 24, 1939
4. 5.7 187 km SSE of False Pass, Alaska · 38 km S of this epicentre Mar 13, 1965
5. 5.0 121 km SSE of False Pass, Alaska · 34 km NNW of this epicentre Dec 27, 1984

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 53.6317, -162.2706. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.2 117 km SSE of False Pass, Alaska 13:23 UTC
2. 2.2 128 km SSE of King Cove, Alaska 12:45 UTC
3. 2.2 166 km S of King Cove, Alaska 19:22 UTC
4. 4.4 185 km S of King Cove, Alaska 15:50 UTC
5. 2.2 135 km S of King Cove, Alaska 17:24 UTC
6. 2.8 197 km S of King Cove, Alaska 08:08 UTC
7. 2.7 126 km SSE of King Cove, Alaska 03:45 UTC
8. 2.6 113 km S of King Cove, Alaska 18:19 UTC
9. 2.4 145 km SSE of False Pass, Alaska 22:22 UTC
10. 2.7 202 km SSE of False Pass, Alaska 13:26 UTC
11. 2.7 190 km SSE of False Pass, Alaska 09:29 UTC
12. 3.8 121 km SSE of False Pass, Alaska 08:37 UTC
13. 2.7 122 km SSE of False Pass, Alaska 20:42 UTC
14. 2.2 113 km SSE of False Pass, Alaska 20:43 UTC
15. 2.4 151 km SSE of King Cove, Alaska 16:06 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 00:34 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.