94 km SSE of Perryville, Alaska

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 92 km (57 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 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 11,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 500× the energy of this one
3. Magna, Utah 2020 M 5.7 350× the energy of this one
4. This earthquake M 4.0 about 15 tons of TNT
5. Around the size people start to feel M 3.0 this one released 32× 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 7.8 on 2020-07-22 — about 500,000 times the energy of this one.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

1. 8.2 1938 Semidi Islands, Alaska Earthquake · 38 km ENE of this epicentre Nov 10, 1938
2. 6.6 104 km SSE of Perryville, Alaska · 12 km SE of this epicentre Nov 11, 1938
3. 6.5 94 km ESE of Sand Point, Alaska · 32 km WSW of this epicentre Feb 14, 1983
4. 6.2 64 km SSE of Perryville, Alaska · 33 km N of this epicentre Jul 28, 1927
5. 6.2 74 km SE of Perryville, Alaska · 39 km NE 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 55.0937, -158.7657. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.6 135 km SSE of Perryville, Alaska 05:37 UTC
2. 2.7 86 km S of Perryville, Alaska 05:15 UTC
3. 2.2 96 km SSE of Perryville, Alaska 04:52 UTC
4. 2.2 110 km SSE of Perryville, Alaska 04:26 UTC
5. 2.6 91 km S of Perryville, Alaska 02:53 UTC
6. 2.1 Alaska Peninsula 02:42 UTC
7. 2.9 88 km S of Perryville, Alaska 23:32 UTC
8. 2.6 105 km SSE of Perryville, Alaska 22:20 UTC
9. 2.9 98 km SSE of Perryville, Alaska 21:53 UTC
10. 2.6 110 km SSE of Perryville, Alaska 18:31 UTC
11. 2.7 102 km SSE of Perryville, Alaska 17:32 UTC
12. 2.2 93 km SSE of Perryville, Alaska 17:09 UTC
13. 2.4 98 km SSE of Perryville, Alaska 16:48 UTC
14. 2.4 97 km SSE of Perryville, Alaska 15:50 UTC
15. 2.6 137 km SSE of Perryville, Alaska 15:33 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 18:20 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.