55 km SSE of Unalaska, Alaska

Yes. A magnitude 1.7 earthquake was recorded 55 km SSE of Unalaska, Alaska, at 3:22 pm AKDT on 29 July 2020 (23:22 UTC), 35 km deep.

2020-07-29 23:22 UTC · 35 km deep · released about 11 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: 2020-07-29 23:22 UTC
Magnitude: M 1.7 (ml)
Depth: 35 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 2286 days ago · we first saw it 2286 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 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
Around the size people start to feel M 3.0 89× the energy of this one
This earthquake M 1.7 about 11 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 4.8 on 2019-09-27 — about 45,000 times the energy of this one.

Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:

6.8 68 km SSW of Unalaska, Alaska · 45 km WSW of this epicentre Mar 29, 1957
6.2 57 km SE of Unalaska, Alaska · 31 km ENE of this epicentre Sep 9, 1942
6.2 36 km ESE of Unalaska, Alaska · 38 km NNE of this epicentre Dec 9, 1942
6.2 74 km SSW of Unalaska, Alaska · 46 km WSW of this epicentre Oct 31, 1985
6.1 56 km SSW of Unalaska, Alaska · 32 km W of this epicentre Jul 24, 1938

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.

1.6 76 km SSW of Unalaska, Alaska 15:47 UTC
3.5 68 km SE of Unalaska, Alaska 16:17 UTC
2.0 24 km ESE of Unalaska, Alaska 11:01 UTC
3.1 84 km S of Unalaska, Alaska 04:29 UTC
2.9 42 km SSW of Unalaska, Alaska 08:02 UTC
2.7 56 km ESE of Unalaska, Alaska 08:28 UTC
1.7 66 km S of Unalaska, Alaska 07:11 UTC
4.0 67 km SE of Unalaska, Alaska 22:14 UTC
3.8 29 km SE of Unalaska, Alaska 07:19 UTC
1.7 24 km SE of Unalaska, Alaska 06:06 UTC
2.6 70 km SSE of Unalaska, Alaska 09:55 UTC
1.6 37 km SSE of Unalaska, Alaska 04:58 UTC
1.8 64 km S of Unalaska, Alaska 16:13 UTC
2.6 65 km S of Unalaska, Alaska 15:17 UTC
2.2 90 km S of Unalaska, Alaska 00:19 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:26 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.