94 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 20 km (12 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 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
3. Around the size people start to feel M 3.0 5.6× the energy of this one
4. This earthquake M 2.5 about 170 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 5.0 on 2020-08-20 — about 5,600 times the energy of this one.

Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:

1. 6.5 88 km SE of False Pass, Alaska · 10 km NNE of this epicentre Jun 21, 1987
2. 5.8 112 km SE of False Pass, Alaska · 21 km ESE of this epicentre Feb 24, 1939
3. 5.8 60 km SSW of King Cove, Alaska · 46 km N of this epicentre May 6, 1956
4. 5.7 88 km SE of False Pass, Alaska · 11 km NNE of this epicentre Apr 26, 1965
5. 5.7 99 km SE of False Pass, Alaska · 8 km E of this epicentre Nov 6, 2011

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 54.1286, -162.6637. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.6 83 km S of King Cove, Alaska 19:21 UTC
2. 1.7 76 km SSE of False Pass, Alaska 10:43 UTC
3. 2.6 85 km SE of False Pass, Alaska 05:43 UTC
4. 3.3 124 km SSE of False Pass, Alaska 09:53 UTC
5. 1.6 56 km SSW of King Cove, Alaska 08:09 UTC
6. 1.9 83 km S of King Cove, Alaska 07:21 UTC
7. 1.6 56 km SSW of King Cove, Alaska 13:37 UTC
8. 3.2 73 km S of King Cove, Alaska 15:58 UTC
9. 2.6 76 km SE of False Pass, Alaska 11:06 UTC
10. 2.6 Alaska Peninsula 09:27 UTC
11. 2.7 92 km SSE of False Pass, Alaska 07:37 UTC
12. 2.6 93 km S of False Pass, Alaska 07:37 UTC
13. 2.2 99 km S of King Cove, Alaska 17:23 UTC
14. 2.9 73 km SE of False Pass, Alaska 02:38 UTC
15. 2.4 64 km S of King Cove, Alaska 23:57 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:37 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.