141 km S of Unalaska, Alaska

2016-08-31 06:31 UTC · 26 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: 2016-08-31 06:31 UTC
Magnitude: M 2.3 (ml)
Depth: 26 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 2693 days ago · we first saw it 2693 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

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.

Where

Map loads when it scrolls into view

Epicentre 52.6017, -166.6708. Map © OpenStreetMap contributors.

Aftershocks so far

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

3.8 170 km ESE of Nikolski, Alaska 04:51 UTC
2.7 156 km ESE of Nikolski, Alaska 00:04 UTC
2.8 155 km ESE of Nikolski, Alaska 22:56 UTC
5.9 163 km ESE of Nikolski, Alaska 16:36 UTC
5.3 163 km ESE of Nikolski, Alaska 16:07 UTC
2.1 101 km SSW of Unalaska, Alaska 00:20 UTC
2.1 130 km S of Unalaska, Alaska 18:44 UTC
2.1 126 km S of Unalaska, Alaska 07:58 UTC
2.3 126 km S of Unalaska, Alaska 06:36 UTC
4.0 130 km ESE of Nikolski, Alaska 06:26 UTC
2.1 121 km S of Unalaska, Alaska 02:19 UTC
2.3 114 km S of Unalaska, Alaska 17:58 UTC
2.1 126 km ESE of Nikolski, Alaska 04:23 UTC
2.2 106 km S of Unalaska, Alaska 02:40 UTC
2.1 133 km S of Unalaska, Alaska 14:24 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 18:14 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 5.4 on 2016-07-26 — it released about 45,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.