211 km WSW of Adak, Alaska

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 710,000× the energy of this one
2. Magna, Utah 2020 M 5.7 500,000× the energy of this one
3. Around the size people start to feel M 3.0 45× the energy of this one
4. This earthquake M 1.9 about 21 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 6.1 on 2021-09-24 — about 2,000,000 times the energy of this one.

Before 2016, the USGS record lists 183 earthquakes of M5 or more within 50 km; the five largest:

1. 7.2 238 km WSW of Adak, Alaska · 27 km WSW of this epicentre Mar 22, 1905
2. 7.2 162 km WSW of Adak, Alaska · 48 km ENE of this epicentre Mar 16, 1957
3. 7.2 207 km WSW of Adak, Alaska · 9 km N of this epicentre Dec 19, 2007
4. 6.9 203 km WSW of Adak, Alaska · 10 km NNE of this epicentre Mar 31, 1913
5. 6.9 231 km WSW of Adak, Alaska · 22 km W of this epicentre May 14, 1969

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 51.2817, -179.5325. Map © OpenStreetMap contributors.

Aftershocks so far

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

1. 2.1 194 km W of Adak, Alaska 20:34 UTC
2. 2.3 236 km WSW of Adak, Alaska 02:12 UTC
3. 3.8 209 km WSW of Adak, Alaska 22:55 UTC
4. 2.0 Andreanof Islands, Aleutian Islands, Alaska 13:18 UTC
5. 2.0 236 km WSW of Adak, Alaska 13:15 UTC
6. 2.0 237 km WSW of Adak, Alaska 13:12 UTC
7. 2.0 235 km WSW of Adak, Alaska 13:08 UTC
8. 2.7 227 km W of Adak, Alaska 17:26 UTC
9. 1.8 200 km WSW of Adak, Alaska 14:24 UTC
10. 2.8 185 km WSW of Adak, Alaska 04:37 UTC
11. 2.0 195 km W of Adak, Alaska 23:24 UTC
12. 4.0 201 km WSW of Adak, Alaska 02:23 UTC
13. 3.0 214 km WSW of Adak, Alaska 20:28 UTC
14. 1.5 211 km W of Adak, Alaska 10:44 UTC
15. 1.6 175 km WSW of Adak, Alaska 09:06 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 07:18 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.