151 km S of Atka, Alaska

Yes. A magnitude 2.3 earthquake was recorded 151 km S of Atka, Alaska at 19:16 UTC on 2017-09-09, 18 km deep.

2017-09-09 19:16 UTC · 18 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: 2017-09-09 19:16 UTC
Magnitude: M 2.3 (ml)
Depth: 18 km below the surface
Felt: no reports yet
Nearest mapped fault: Alaska-Aleutian subduction zone, 15 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 1193 days ago · we first saw it 1193 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 9 km (6 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 4.2 on 2016-03-19 — about 710 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

5.8 131 km S of Atka, Alaska · 23 km NNW of this epicentre Apr 24, 1928
5.6 185 km S of Atka, Alaska · 40 km SW of this epicentre May 25, 1988
5.0 108 km S of Atka, Alaska · 43 km N of this epicentre Jan 21, 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

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

2.9 109 km S of Atka, Alaska 09:03 UTC
2.3 155 km S of Atka, Alaska 22:30 UTC
1.9 196 km S of Atka, Alaska 06:35 UTC
2.6 174 km S of Atka, Alaska 07:38 UTC
3.1 145 km S of Atka, Alaska 14:49 UTC
2.1 125 km S of Atka, Alaska 04:28 UTC
2.1 196 km S of Atka, Alaska 10:49 UTC
2.1 166 km S of Atka, Alaska 01:55 UTC
3.9 190 km S of Atka, Alaska 13:05 UTC
1.9 133 km S of Atka, Alaska 14:49 UTC
1.9 127 km S of Atka, Alaska 16:19 UTC
2.5 177 km SSW of Atka, Alaska 09:13 UTC
2.3 146 km S of Atka, Alaska 21:55 UTC
3.2 123 km S of Atka, Alaska 03:51 UTC
2.5 186 km S of Atka, Alaska 19:30 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 03:24 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.