166 km SW of Adak, Alaska

2016-09-11 00:33 UTC · 33 km deep · released about 950 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: 2016-09-11 00:33 UTC
Magnitude: M 3.0 (ml)
Depth: 33 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1152 days ago · we first saw it 1152 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

Northridge, California 1994 M 6.7 350,000× the energy of this one
Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
Magna, Utah 2020 M 5.7 11,000× the energy of this one
This earthquake M 3.0 about 950 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.

Where

Map loads when it scrolls into view

Epicentre 51.0450, -178.6232. Map © OpenStreetMap contributors.

Aftershocks so far

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

2.2 190 km WSW of Adak, Alaska 23:09 UTC
2.1 193 km WSW of Adak, Alaska 05:40 UTC
2.1 165 km WSW of Adak, Alaska 08:15 UTC
2.4 118 km WSW of Adak, Alaska 06:41 UTC
3.5 122 km WSW of Adak, Alaska 14:38 UTC
4.5 134 km WSW of Adak, Alaska 16:18 UTC
2.5 172 km WSW of Adak, Alaska 21:45 UTC
2.8 187 km WSW of Adak, Alaska 06:46 UTC
4.1 146 km SW of Adak, Alaska 18:10 UTC
2.1 166 km WSW of Adak, Alaska 15:13 UTC
2.2 148 km WSW of Adak, Alaska 10:07 UTC
2.8 130 km WSW of Adak, Alaska 17:42 UTC
2.3 141 km WSW of Adak, Alaska 06:36 UTC
4.1 129 km WSW of Adak, Alaska 14:44 UTC
2.5 155 km WSW of Adak, Alaska 15:10 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 04:08 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.