40 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 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 6.6 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 2,300,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
3. Around the size people start to feel M 3.0 140× the energy of this one
4. This earthquake M 1.6 about 6.6 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 5.2 on 2018-02-16 — about 290,000 times the energy of this one.

Before 2016, the USGS record lists 53 earthquakes of M5 or more within 50 km; the five largest:

1. 7.9 77 km WSW of Adak, Alaska · 49 km SW of this epicentre Jun 10, 1996
2. 7.6 5 km WNW of Adak, Alaska · 36 km E of this epicentre Feb 14, 1905
3. 7.1 60 km SW of Adak, Alaska · 49 km S of this epicentre Mar 12, 1957
4. 6.9 78 km WSW of Adak, Alaska · 48 km SW of this epicentre Mar 20, 1999
5. 6.6 61 km W of Adak, Alaska · 22 km WSW of this epicentre May 2, 2008

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 51.9195, -177.2198. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 1.8 59 km WSW of Adak, Alaska 10:07 UTC
2. 1.7 59 km W of Adak, Alaska 06:06 UTC
3. 1.6 74 km WSW of Adak, Alaska 11:04 UTC
4. 1.8 60 km SW of Adak, Alaska 18:36 UTC
5. 1.9 71 km WSW of Adak, Alaska 07:34 UTC
6. 1.9 70 km SW of Adak, Alaska 08:42 UTC
7. 1.9 47 km SW of Adak, Alaska 19:45 UTC
8. 1.6 62 km W of Adak, Alaska 11:01 UTC
9. 1.8 66 km WSW of Adak, Alaska 03:17 UTC
10. 1.8 24 km SSW of Adak, Alaska 07:08 UTC
11. 1.7 16 km WNW of Adak, Alaska 03:09 UTC
12. 1.9 59 km WSW of Adak, Alaska 16:07 UTC
13. 2.0 34 km SW of Adak, Alaska 09:28 UTC
14. 3.1 48 km WSW of Adak, Alaska 13:31 UTC
15. 2.4 46 km W of Adak, Alaska 16:01 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 05:57 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.