123 km SE of Perryville, 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 78 km (48 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 7.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 22,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 1,000× the energy of this one
3. Magna, Utah 2020 M 5.7 710× the energy of this one
4. This earthquake M 3.8 about 7.6 tons of TNT
5. Around the size people start to feel M 3.0 this one released 16× more

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 5.7 on 2016-05-31 — about 710 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

1. 8.2 1938 Semidi Islands, Alaska Earthquake · 22 km NNW of this epicentre Nov 10, 1938
2. 6.9 105 km ESE of Perryville, Alaska · 48 km NNE of this epicentre Nov 17, 1938
3. 6.6 104 km SSE of Perryville, Alaska · 41 km W of this epicentre Nov 11, 1938
4. 6.2 143 km SE of Perryville, Alaska · 21 km SE of this epicentre Mar 25, 1927
5. 6.2 74 km SE of Perryville, Alaska · 49 km NNW of this epicentre Aug 6, 1927

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 55.0088, -158.0028. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.4 136 km SE of Perryville, Alaska 12:17 UTC
2. 2.5 100 km SE of Perryville, Alaska 11:51 UTC
3. 2.6 119 km SE of Perryville, Alaska 11:36 UTC
4. 3.6 139 km SE of Perryville, Alaska 11:04 UTC
5. 3.0 125 km SE of Perryville, Alaska 10:58 UTC
6. 2.6 139 km SE of Perryville, Alaska 10:47 UTC
7. 3.3 131 km SSE of Perryville, Alaska 10:16 UTC
8. 3.4 140 km SE of Perryville, Alaska 10:01 UTC
9. 3.5 124 km SE of Perryville, Alaska 09:37 UTC
10. 2.8 134 km SE of Perryville, Alaska 09:35 UTC
11. 3.3 143 km SE of Perryville, Alaska 09:07 UTC
12. 2.5 100 km SSE of Perryville, Alaska 09:03 UTC
13. 3.8 142 km SE of Perryville, Alaska 08:55 UTC
14. 3.8 135 km SE of Perryville, Alaska 08:54 UTC
15. 2.7 133 km SSE of Perryville, Alaska 08:50 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:26 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.