62 km SE of Perryville, Alaska

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 3 km (2 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 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 710,000× the energy of this one
2. Magna, Utah 2020 M 5.7 500,000× the energy of this one
3. Around the size people start to feel M 3.0 45× the energy of this one
4. This earthquake M 1.9 about 21 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 8.2 on 2021-07-29 — about 2,800,000,000 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

1. 8.2 1938 Semidi Islands, Alaska Earthquake · 45 km SSE of this epicentre Nov 10, 1938
2. 6.9 105 km ESE of Perryville, Alaska · 43 km ESE of this epicentre Nov 17, 1938
3. 6.2 64 km SSE of Perryville, Alaska · 31 km SW of this epicentre Jul 28, 1927
4. 6.2 74 km SE of Perryville, Alaska · 22 km S of this epicentre Aug 6, 1927
5. 6.0 98 km ESE of Perryville, Alaska · 36 km ESE of this epicentre Jan 2, 1985

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 55.5736, -158.3529. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.3 Alaska Peninsula 00:50 UTC
2. 2.6 93 km SE of Perryville, Alaska 16:36 UTC
3. 2.3 Alaska Peninsula 06:19 UTC
4. 1.7 52 km SE of Perryville, Alaska 01:42 UTC
5. 2.2 60 km SE of Perryville, Alaska 16:36 UTC
6. 2.3 76 km ESE of Perryville, Alaska 18:34 UTC
7. 2.7 Alaska Peninsula 01:41 UTC
8. 2.4 36 km SSE of Perryville, Alaska 08:11 UTC
9. 2.1 36 km SSE of Perryville, Alaska 15:38 UTC
10. 3.1 47 km SE of Perryville, Alaska 14:08 UTC
11. 2.3 67 km SSE of Chignik, Alaska 08:42 UTC
12. 1.9 36 km ESE of Perryville, Alaska 23:13 UTC
13. 1.9 31 km SE of Perryville, Alaska 16:20 UTC
14. 2.1 72 km SSE of Perryville, Alaska 03:19 UTC
15. 2.1 29 km ENE of Perryville, Alaska 09:40 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:18 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.