140 km SW of Adak, Alaska

Yes. A magnitude 3.1 earthquake was recorded 140 km SW of Adak, Alaska at 14:42 UTC on 2021-10-05, 28 km deep.

2021-10-05 14:42 UTC · 28 km deep · released about 1,300 lb of TNT

Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.

When: 2021-10-05 14:42 UTC
Magnitude: M 3.1 (ml)
Depth: 28 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1799 days ago · we first saw it 1799 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 30 km (19 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

Northridge, California 1994 M 6.7 250,000× the energy of this one
Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
Magna, Utah 2020 M 5.7 7,900× the energy of this one
This earthquake M 3.1 about 1,300 lb of TNT
Around the size people start to feel M 3.0 this one released 1.4× more

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 6.5 on 2018-08-15 — about 130,000 times the energy of this one.

Before 2016, the USGS record lists 192 earthquakes of M5 or more within 50 km; the five largest:

7.0 114 km WSW of Adak, Alaska · 39 km N of this epicentre Jul 5, 1929
7.0 148 km WSW of Adak, Alaska · 35 km NW of this epicentre Mar 11, 1957
6.9 151 km WSW of Adak, Alaska · 41 km NW of this epicentre May 15, 1993
6.8 111 km SW of Adak, Alaska · 28 km NE of this epicentre Jan 4, 1912
6.6 152 km WSW of Adak, Alaska · 48 km NW 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

Map loads when it scrolls into view

Aftershocks so far

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

2.1 130 km SW of Adak, Alaska 03:16 UTC
1.7 133 km WSW of Adak, Alaska 23:41 UTC
1.9 143 km WSW of Adak, Alaska 00:29 UTC
1.9 115 km SW of Adak, Alaska 08:12 UTC
2.5 113 km WSW of Adak, Alaska 19:54 UTC
2.0 95 km WSW of Adak, Alaska 12:13 UTC
1.7 138 km WSW of Adak, Alaska 14:32 UTC
1.8 136 km SW of Adak, Alaska 08:07 UTC
2.8 147 km WSW of Adak, Alaska 19:39 UTC
1.9 137 km WSW of Adak, Alaska 16:19 UTC
1.9 146 km WSW of Adak, Alaska 14:59 UTC
2.9 114 km WSW of Adak, Alaska 04:18 UTC
2.0 142 km WSW of Adak, Alaska 03:55 UTC
1.9 142 km WSW of Adak, Alaska 12:22 UTC
2.2 129 km SW of Adak, Alaska 09:17 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 07:37 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.