130 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 it was probably too small to be felt, even directly above it. 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 60 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 250,000× the energy of this one
2. Magna, Utah 2020 M 5.7 180,000× the energy of this one
3. Around the size people start to feel M 3.0 16× the energy of this one
4. This earthquake M 2.2 about 60 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 1,000,000,000 times the energy of this one.

Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:

1. 8.2 1938 Semidi Islands, Alaska Earthquake · 38 km W of this epicentre Nov 10, 1938
2. 6.9 105 km ESE of Perryville, Alaska · 31 km NNW of this epicentre Nov 17, 1938
3. 6.7 121 km SE of Chignik, Alaska · 44 km NE of this epicentre Feb 13, 1979
4. 6.2 143 km SE of Perryville, Alaska · 29 km SSW of this epicentre Mar 25, 1927
5. 6.0 98 km ESE of Perryville, Alaska · 36 km NNW 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 55.1386, -157.5883. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.2 121 km SE of Perryville, Alaska 21:24 UTC
2. 2.5 128 km SSE of Chignik, Alaska 18:21 UTC
3. 2.3 111 km SSE of Chignik, Alaska 15:03 UTC
4. 2.5 132 km SE of Perryville, Alaska 14:30 UTC
5. 2.1 113 km SSE of Chignik, Alaska 04:53 UTC
6. 2.2 south of Alaska 22:08 UTC
7. 3.2 119 km SSE of Chignik, Alaska 19:24 UTC
8. 3.3 159 km SSE of Chignik, Alaska 08:59 UTC
9. 3.3 152 km SSE of Chignik, Alaska 14:50 UTC
10. 3.6 136 km SE of Perryville, Alaska 13:02 UTC
11. 2.7 115 km SE of Perryville, Alaska 04:35 UTC
12. 2.5 115 km SE of Perryville, Alaska 03:57 UTC
13. 2.9 129 km SE of Perryville, Alaska 11:22 UTC
14. 2.5 125 km SE of Perryville, Alaska 07:49 UTC
15. 3.1 129 km SE of Perryville, Alaska 16:49 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 10:00 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.