106 km S of Atka, 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 8 km (5 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 30 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 500,000× the energy of this one
2. Magna, Utah 2020 M 5.7 350,000× the energy of this one
3. Around the size people start to feel M 3.0 32× the energy of this one
4. This earthquake M 2.0 about 30 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 6.3 on 2016-03-12 — about 2,800,000 times the energy of this one.

Before 2016, the USGS record lists 108 earthquakes of M5 or more within 50 km; the five largest:

1. 6.6 62 km SSE of Atka, Alaska · 50 km NNE of this epicentre Mar 10, 1957
2. 6.6 89 km S of Atka, Alaska · 20 km NNW of this epicentre Mar 10, 1957
3. 6.3 99 km SSW of Atka, Alaska · 47 km WNW of this epicentre May 7, 1986
4. 6.1 65 km S of Atka, Alaska · 42 km N of this epicentre Jul 19, 1933
5. 6.1 87 km S of Atka, Alaska · 20 km NNE of this epicentre Jun 9, 1983

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 51.2361, -174.1722. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 3.3 90 km S of Atka, Alaska 06:49 UTC
2. 1.8 105 km S of Atka, Alaska 06:21 UTC
3. 2.5 88 km S of Atka, Alaska 22:08 UTC
4. 2.6 Andreanof Islands, Aleutian Islands, Alaska 07:13 UTC
5. 2.4 89 km S of Atka, Alaska 20:50 UTC
6. 2.3 99 km S of Atka, Alaska 16:14 UTC
7. 2.1 86 km SSE of Atka, Alaska 14:17 UTC
8. 2.3 83 km SSE of Atka, Alaska 10:53 UTC
9. 1.9 71 km SSE of Atka, Alaska 07:38 UTC
10. 4.0 122 km SSE of Atka, Alaska 19:27 UTC
11. 2.3 96 km S of Atka, Alaska 15:43 UTC
12. 3.9 94 km S of Atka, Alaska 02:42 UTC
13. 2.6 93 km S of Atka, Alaska 00:41 UTC
14. 2.5 69 km SSE of Atka, Alaska 19:23 UTC
15. 2.6 85 km SSW of Atka, Alaska 16:10 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 11:34 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.