149 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 16 km (10 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 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
3. Around the size people start to feel M 3.0 22× the energy of this one
4. This earthquake M 2.1 about 43 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 6.9 on 2021-08-14 — about 16,000,000 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. 6.9 105 km ESE of Perryville, Alaska · 50 km NNW of this epicentre Nov 17, 1938
2. 6.2 143 km SE of Perryville, Alaska · 24 km WSW of this epicentre Mar 25, 1927
3. 5.9 182 km SE of Perryville, Alaska · 40 km S of this epicentre Dec 23, 1938
4. 5.5 160 km SE of Perryville, Alaska · 12 km SSE of this epicentre Mar 10, 2012
5. 5.2 116 km SE of Perryville, Alaska · 34 km WNW of this epicentre Dec 19, 2004

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 54.9997, -157.4083. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.5 148 km SE of Chignik, Alaska 23:23 UTC
2. 3.1 188 km SE of Perryville, Alaska 22:48 UTC
3. 2.5 120 km ESE of Perryville, Alaska 23:28 UTC
4. 3.5 184 km SE of Perryville, Alaska 19:49 UTC
5. 3.0 179 km SE of Perryville, Alaska 22:53 UTC
6. 3.9 125 km SE of Perryville, Alaska 22:38 UTC
7. 4.8 184 km SE of Perryville, Alaska 15:16 UTC
8. 3.4 142 km SE of Perryville, Alaska 13:00 UTC
9. 2.9 186 km SE of Perryville, Alaska 04:23 UTC
10. 2.3 124 km SE of Perryville, Alaska 06:53 UTC
11. 2.6 130 km SE of Perryville, Alaska 01:16 UTC
12. 3.0 121 km SE of Perryville, Alaska 19:20 UTC
13. 2.5 180 km SE of Perryville, Alaska 06:55 UTC
14. 3.1 180 km SE of Perryville, Alaska 17:06 UTC
15. 3.3 186 km SE of Perryville, Alaska 20:39 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 12:51 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.