173 km SSE of Adak, Alaska

Yes. A magnitude 4.1 earthquake was recorded 173 km SSE of Adak, Alaska at 15:21 UTC on 2018-08-29, 10 km deep.

2018-08-29 15:21 UTC · 10 km deep · released about 21 tons 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: 2018-08-29 15:21 UTC
Magnitude: M 4.1 (mb)
Depth: 10 km below the surface
Felt: no reports yet
Nearest mapped fault: Alaska-Aleutian subduction zone, 8 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 1186 days ago · we first saw it 1186 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 104 km (65 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 21 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

Northridge, California 1994 M 6.7 7,900× the energy of this one
Mineral, Virginia 2011 M 5.8 350× the energy of this one
Magna, Utah 2020 M 5.7 250× the energy of this one
This earthquake M 4.1 about 21 tons of TNT
Around the size people start to feel M 3.0 this one released 45× 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 5.0 on 2016-06-29 — about 22 times the energy of this one.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

7.0 153 km SE of Adak, Alaska · 40 km NNE of this epicentre Jan 17, 1903
6.9 216 km SSE of Adak, Alaska · 45 km SSE of this epicentre Sep 17, 1911
6.3 159 km SSE of Adak, Alaska · 19 km WNW of this epicentre Apr 3, 1915
6.3 204 km SSE of Adak, Alaska · 37 km S of this epicentre Feb 22, 1958
6.1 193 km SE of Adak, Alaska · 34 km E of this epicentre Aug 19, 1992

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

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

2.2 197 km SSE of Adak, Alaska 22:15 UTC
2.1 179 km SE of Adak, Alaska 09:47 UTC
2.1 153 km SSE of Adak, Alaska 09:32 UTC
3.0 187 km SSE of Adak, Alaska 19:19 UTC
1.6 206 km SSE of Adak, Alaska 23:55 UTC
1.8 171 km SSW of Atka, Alaska 11:57 UTC
1.8 161 km SE of Adak, Alaska 23:37 UTC
2.0 170 km SE of Adak, Alaska 16:32 UTC
2.2 163 km SE of Adak, Alaska 02:12 UTC
2.0 152 km SE of Adak, Alaska 03:44 UTC
2.3 161 km SSE of Adak, Alaska 03:49 UTC
2.5 188 km SSE of Adak, Alaska 12:34 UTC
2.6 170 km SSE of Adak, Alaska 05:43 UTC
2.9 187 km SSE of Adak, Alaska 05:47 UTC
4.3 180 km SSW of Atka, Alaska 18:07 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 07:54 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.