Fox Islands, Aleutian Islands, Alaska

Yes. A magnitude 3.1 earthquake was recorded in the Fox Islands, Aleutian Islands, Alaska at 20:15 UTC on 2016-12-03, 37 km deep.

2016-12-03 20:15 UTC · 37 km deep · released about 1,300 lb of TNT

Felt it? Tell USGS Check my area

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: 2016-12-03 20:15 UTC
Magnitude: M 3.1 (ml)
Depth: 37 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1199 days ago · we first saw it 1199 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 20 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 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 4.6 on 2016-01-18 — about 180 times the energy of this one.

Before 2016, the USGS record lists 69 earthquakes of M5 or more within 50 km; the five largest:

6.6 135 km SW of Nikolski, Alaska · 49 km E of this epicentre Dec 23, 1906
6.2 179 km SW of Nikolski, Alaska · 20 km SSE of this epicentre Jun 4, 1956
6.2 Fox Islands, Aleutian Islands, Alaska · 35 km S of this epicentre Mar 10, 1957
6.1 207 km ESE of Atka, Alaska · 48 km SW of this epicentre Mar 13, 1957
6.1 Fox Islands, Aleutian Islands, Alaska · 15 km SSW of this epicentre Jan 11, 1961

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.

2.4 137 km SW of Nikolski, Alaska 11:37 UTC
3.3 133 km WSW of Nikolski, Alaska 11:18 UTC
4.6 161 km SW of Nikolski, Alaska 01:34 UTC
3.3 133 km WSW of Nikolski, Alaska 19:37 UTC
3.1 188 km WSW of Nikolski, Alaska 14:13 UTC
3.1 132 km WSW of Nikolski, Alaska 18:15 UTC
3.4 134 km SW of Nikolski, Alaska 05:35 UTC
2.6 140 km SW of Nikolski, Alaska 06:08 UTC
2.6 136 km SW of Nikolski, Alaska 05:47 UTC
2.5 186 km WSW of Nikolski, Alaska 13:19 UTC
2.6 180 km SW of Nikolski, Alaska 10:35 UTC
2.3 179 km SW of Nikolski, Alaska 02:26 UTC
3.5 182 km WSW of Nikolski, Alaska 03:58 UTC
3.1 160 km WSW of Nikolski, Alaska 17:03 UTC
2.4 139 km SW of Nikolski, Alaska 13:34 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:31 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.