148 km S of Unalaska, Alaska

Yes. A magnitude 1.9 earthquake was recorded 148 km S of Unalaska, Alaska, at 6:20 pm AKDT on 6 August 2016 (02:20 UTC), 23 km deep.

2016-08-07 02:20 UTC · 23 km deep · released about 21 lb of TNT

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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: 2016-08-07 02:20 UTC
Magnitude: M 1.9 (ml)
Depth: 23 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1200 days ago · we first saw it 1200 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 710,000× the energy of this one
Magna, Utah 2020 M 5.7 500,000× the energy of this one
Around the size people start to feel M 3.0 45× the energy of this one
This earthquake M 1.9 about 21 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 5.4 on 2016-07-26 — about 180,000 times the energy of this one.

Before 2016, the USGS record lists 34 earthquakes of M5 or more within 50 km; the five largest:

6.5 183 km S of Unalaska, Alaska · 36 km SSE of this epicentre Apr 19, 1957
6.5 127 km E of Nikolski, Alaska · 42 km WNW of this epicentre Oct 13, 2009
6.4 123 km ESE of Nikolski, Alaska · 44 km W of this epicentre Oct 13, 2009
6.3 136 km ESE of Nikolski, Alaska · 31 km WNW of this epicentre Jan 12, 1952
6.3 130 km ESE of Nikolski, Alaska · 37 km WNW of this epicentre Jun 12, 1958

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

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Aftershocks so far

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

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
2.5 180 km S of Unalaska, Alaska 17:26 UTC
2.2 106 km S of Unalaska, Alaska 02:40 UTC
2.1 133 km S of Unalaska, Alaska 14:24 UTC
2.1 140 km S of Unalaska, Alaska 13:56 UTC
3.6 123 km S of Unalaska, Alaska 20:08 UTC
2.6 124 km S of Unalaska, Alaska 03:46 UTC
2.1 126 km S of Unalaska, Alaska 01:18 UTC
1.8 131 km S of Unalaska, Alaska 08:24 UTC
2.5 128 km S of Unalaska, Alaska 03:23 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:03 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.