121 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 6 km (4 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 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
3. Around the size people start to feel M 3.0 130× the energy of this one
4. This earthquake M 1.6 about 7.6 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 5.3 on 2016-07-03 — about 350,000 times the energy of this one.

Before 2016, the USGS record lists 78 earthquakes of M5 or more within 50 km; the five largest:

1. 7.0 114 km WSW of Adak, Alaska · 49 km SSE of this epicentre Jul 5, 1929
2. 6.5 111 km WSW of Adak, Alaska · 46 km SSE of this epicentre Jun 8, 1996
3. 6.4 118 km WSW of Adak, Alaska · 32 km SSE of this epicentre Sep 26, 2012
4. 6.3 155 km WSW of Adak, Alaska · 50 km SSW of this epicentre Jul 17, 1929
5. 6.3 128 km W of Adak, Alaska · 14 km NNW of this epicentre May 10, 1939

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 51.8718, -178.3940. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 140 km WSW of Adak, Alaska 18:03 UTC
2. 1.9 150 km W of Adak, Alaska 06:09 UTC
3. 2.4 114 km WSW of Adak, Alaska 01:28 UTC
4. 2.7 116 km WSW of Adak, Alaska 17:25 UTC
5. 3.8 139 km W of Adak, Alaska 10:07 UTC
6. 2.2 132 km WSW of Adak, Alaska 18:24 UTC
7. 3.1 143 km W of Adak, Alaska 20:06 UTC
8. 2.9 114 km WSW of Adak, Alaska 20:06 UTC
9. 1.7 114 km WSW of Adak, Alaska 00:14 UTC
10. 2.8 108 km WSW of Adak, Alaska 20:51 UTC
11. 2.4 143 km WSW of Adak, Alaska 06:45 UTC
12. 1.8 110 km WSW of Adak, Alaska 20:21 UTC
13. 2.0 129 km W of Adak, Alaska 17:55 UTC
14. 3.0 111 km WSW of Adak, Alaska 12:16 UTC
15. 2.3 130 km W of Adak, Alaska 06:03 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 19:22 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.