176 km ESE of Chignik, Alaska

Yes. A magnitude 3.3 earthquake was recorded 176 km ESE of Chignik, Alaska at 00:58 UTC on 2021-07-31, 7.3 km deep.

2021-07-31 00:58 UTC · 7.3 km deep · released about 1.3 tons 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: 2021-07-31 00:58 UTC
Magnitude: M 3.3 (ml)
Depth: 7.3 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1856 days ago · we first saw it 1856 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 51 km (32 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 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

Northridge, California 1994 M 6.7 130,000× the energy of this one
Mineral, Virginia 2011 M 5.8 5,600× the energy of this one
Magna, Utah 2020 M 5.7 4,000× the energy of this one
This earthquake M 3.3 about 1.3 tons of TNT
Around the size people start to feel M 3.0 this one released 2.8× 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 4.8 on 2021-07-29 — about 180 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

7.0 164 km SE of Chignik, Alaska · 48 km SW of this epicentre Sep 4, 1989
6.9 143 km ESE of Chignik, Alaska · 34 km NW of this epicentre Feb 13, 1951
6.9 171 km SW of Akhiok, Alaska · 13 km N of this epicentre Feb 6, 1964
6.2 148 km SSW of Akhiok, Alaska · 44 km ENE of this epicentre Nov 10, 1944
6.1 210 km SE of Chignik, Alaska · 49 km SSE of this epicentre Nov 15, 1955

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

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

2.9 167 km SW of Akhiok, Alaska 11:50 UTC
2.2 161 km SW of Akhiok, Alaska 02:14 UTC
3.0 190 km SE of Chignik, Alaska 19:35 UTC
1.9 165 km SE of Chignik, Alaska 13:56 UTC
2.6 177 km SSW of Akhiok, Alaska 17:37 UTC
2.9 185 km SSW of Akhiok, Alaska 00:34 UTC
1.8 157 km SSW of Akhiok, Alaska 19:45 UTC
3.0 169 km ESE of Chignik, Alaska 10:05 UTC
1.6 south of Alaska 09:35 UTC
2.8 190 km SSW of Akhiok, Alaska 06:38 UTC
3.0 158 km SE of Chignik, Alaska 19:15 UTC
1.9 144 km ESE of Chignik, Alaska 02:51 UTC
2.4 170 km SE of Chignik, Alaska 21:22 UTC
2.6 166 km ESE of Chignik, Alaska 01:41 UTC
2.4 162 km SW of Akhiok, Alaska 11:42 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 11:46 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.