134 km W of Adak, 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 9 km (6 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 6.2 on 2017-05-08 — about 2,000,000 times the energy of this one.

Before 2016, the USGS record lists 140 earthquakes of M5 or more within 50 km; the five largest:

1. 7.2 162 km WSW of Adak, Alaska · 41 km SSW of this epicentre Mar 16, 1957
2. 7.0 114 km WSW of Adak, Alaska · 43 km SE of this epicentre Jul 5, 1929
3. 7.0 148 km WSW of Adak, Alaska · 44 km S of this epicentre Mar 11, 1957
4. 6.9 151 km WSW of Adak, Alaska · 41 km S of this epicentre May 15, 1993
5. 6.6 152 km WSW of Adak, Alaska · 36 km SSW of this epicentre Mar 13, 1957

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 51.7372, -178.5752. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.9 126 km WSW of Adak, Alaska 06:41 UTC
2. 2.2 126 km WSW of Adak, Alaska 05:53 UTC
3. 2.0 132 km W of Adak, Alaska 05:43 UTC
4. 1.6 127 km W of Adak, Alaska 05:35 UTC
5. 2.0 Andreanof Islands, Aleutian Islands, Alaska 05:11 UTC
6. 1.9 123 km WSW of Adak, Alaska 02:36 UTC
7. 1.8 126 km WSW of Adak, Alaska 01:36 UTC
8. 2.3 125 km WSW of Adak, Alaska 00:49 UTC
9. 1.8 123 km WSW of Adak, Alaska 00:19 UTC
10. 1.8 128 km W of Adak, Alaska 00:07 UTC
11. 3.0 126 km WSW of Adak, Alaska 23:46 UTC
12. 1.6 125 km W of Adak, Alaska 23:31 UTC
13. 1.9 127 km WSW of Adak, Alaska 22:52 UTC
14. 2.2 125 km W of Adak, Alaska 22:22 UTC
15. 1.9 123 km WSW of Adak, Alaska 19:22 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:52 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.