161 km S of Atka, Alaska

Yes. A magnitude 2.3 earthquake was recorded 161 km S of Atka, Alaska at 02:47 UTC on 2023-07-23, 5.8 km deep.

2023-07-23 02:47 UTC · 5.8 km deep · released about 85 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: 2023-07-23 02:47 UTC
Magnitude: M 2.3 (ml)
Depth: 5.8 km below the surface
Felt: no reports yet
Nearest mapped fault: Alaska-Aleutian subduction zone, 7 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 1201 days ago · we first saw it 1201 days ago

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 19 km (12 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 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
Magna, Utah 2020 M 5.7 130,000× the energy of this one
Around the size people start to feel M 3.0 11× the energy of this one
This earthquake M 2.3 about 85 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 4.6 on 2023-04-22 — about 2,800 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

6.6 208 km S of Atka, Alaska · 47 km S of this epicentre Apr 30, 1913
6.1 193 km SE of Adak, Alaska · 48 km SW of this epicentre Aug 19, 1992
5.8 131 km S of Atka, Alaska · 30 km N of this epicentre Apr 24, 1928
5.6 178 km SE of Adak, Alaska · 45 km WSW of this epicentre Dec 26, 1971
5.6 185 km S of Atka, Alaska · 26 km SSW of this epicentre May 25, 1988

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

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

2.3 141 km S of Atka, Alaska 05:07 UTC
3.4 201 km SSW of Atka, Alaska 13:11 UTC
3.3 148 km S of Atka, Alaska 03:36 UTC
3.1 185 km S of Atka, Alaska 04:37 UTC
2.9 181 km S of Atka, Alaska 04:50 UTC
3.4 196 km S of Atka, Alaska 20:25 UTC
2.8 162 km S of Atka, Alaska 16:13 UTC
3.4 192 km S of Atka, Alaska 16:24 UTC
2.9 196 km SSW of Atka, Alaska 12:13 UTC
2.8 174 km S of Atka, Alaska 20:51 UTC
2.3 143 km S of Atka, Alaska 11:20 UTC
1.9 159 km SSW of Atka, Alaska 20:47 UTC
2.0 188 km S of Atka, Alaska 15:32 UTC
2.3 187 km S of Atka, Alaska 14:30 UTC
2.3 159 km S of Atka, Alaska 22:14 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 22:09 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.