112 km ENE of Atka, Alaska

Yes. A magnitude 4.9 earthquake was recorded 112 km ENE of Atka, Alaska at 11:23 UTC on 2016-10-20, 131 km deep.

2016-10-20 11:23 UTC · 131 km deep · released about 340 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: 2016-10-20 11:23 UTC
Magnitude: M 4.9 (mb)
Depth: 131 km below the surface
Felt: no reports yet
Measured shaking: intensity III (ShakeMap)
Status: Reviewed by a seismologist

USGS · last changed by USGS 1199 days ago · we first saw it 1199 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 126 km (78 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 340 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.9 would have released about 32 times as much.

Northridge, California 1994 M 6.7 500× the energy of this one
Mineral, Virginia 2011 M 5.8 22× the energy of this one
Magna, Utah 2020 M 5.7 16× the energy of this one
This earthquake M 4.9 about 340 tons of TNT
Around the size people start to feel M 3.0 this one released 710× 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 (31 mi) since our catalogue begins in 2016. The previous largest was M 4.2 on 2016-03-27.

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

5.7 78 km ENE of Atka, Alaska · 33 km WSW of this epicentre May 21, 1971
5.7 89 km E of Atka, Alaska · 49 km SSW of this epicentre Mar 22, 1993
5.5 78 km NE of Atka, Alaska · 39 km W of this epicentre May 24, 2011
5.0 86 km NE of Atka, Alaska · 46 km WNW of this epicentre Jun 29, 1978
5.0 93 km ENE of Atka, Alaska · 24 km SSW of this epicentre Sep 23, 2010

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

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

3.1 70 km E of Atka, Alaska 11:36 UTC
2.8 79 km ENE of Atka, Alaska 16:46 UTC
3.7 77 km E of Atka, Alaska 20:33 UTC
3.1 81 km E of Atka, Alaska 19:14 UTC
3.4 110 km ENE of Atka, Alaska 12:41 UTC
2.3 69 km E of Atka, Alaska 09:01 UTC
2.7 103 km ENE of Atka, Alaska 08:28 UTC
2.4 105 km E of Atka, Alaska 13:13 UTC
2.5 70 km ENE of Atka, Alaska 19:01 UTC
2.7 90 km ENE of Atka, Alaska 04:45 UTC
2.8 89 km ENE of Atka, Alaska 07:15 UTC
4.8 93 km ENE of Atka, Alaska 07:03 UTC
2.4 146 km ENE of Atka, Alaska 10:19 UTC
2.3 73 km ENE of Atka, Alaska 11:48 UTC
1.9 129 km E of Atka, Alaska 10:59 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 05:38 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.