148 km SSE of Chignik, Alaska

Yes. A magnitude 2.8 earthquake was recorded 148 km SSE of Chignik, Alaska at 01:09 UTC on 2021-09-15, 26 km deep.

2021-09-15 01:09 UTC · 26 km deep · released about 480 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: 2021-09-15 01:09 UTC
Magnitude: M 2.8 (ml)
Depth: 26 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1816 days ago · we first saw it 1816 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 8 km (5 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 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
Magna, Utah 2020 M 5.7 22,000× the energy of this one
Around the size people start to feel M 3.0 2× the energy of this one
This earthquake M 2.8 about 480 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 6.9 on 2021-08-14 — about 1,400,000 times the energy of this one.

Before 2016, the USGS record lists 18 earthquakes of M5 or more within 50 km; the five largest:

7.0 164 km SE of Chignik, Alaska · 47 km ENE of this epicentre Sep 4, 1989
6.9 105 km ESE of Perryville, Alaska · 46 km NW of this epicentre Nov 17, 1938
6.7 121 km SE of Chignik, Alaska · 31 km N of this epicentre Feb 13, 1979
6.2 189 km SE of Chignik, Alaska · 45 km ESE of this epicentre Mar 18, 1945
6.0 168 km SE of Chignik, Alaska · 42 km ENE of this epicentre Nov 16, 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

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

4.5 147 km SE of Perryville, Alaska 18:08 UTC
2.7 142 km SE of Perryville, Alaska 18:06 UTC
3.2 142 km SE of Perryville, Alaska 17:54 UTC
2.3 156 km SSE of Chignik, Alaska 21:38 UTC
2.7 140 km SE of Chignik, Alaska 09:30 UTC
2.6 150 km SE of Chignik, Alaska 09:20 UTC
2.5 170 km SE of Chignik, Alaska 00:12 UTC
2.4 102 km SE of Chignik, Alaska 12:09 UTC
3.3 137 km SE of Perryville, Alaska 21:00 UTC
2.3 122 km SE of Chignik, Alaska 19:20 UTC
2.5 146 km SE of Perryville, Alaska 12:49 UTC
2.4 Alaska Peninsula 09:19 UTC
2.8 145 km SSE of Chignik, Alaska 03:10 UTC
2.5 158 km SSE of Chignik, Alaska 10:32 UTC
2.9 190 km SE of Perryville, Alaska 04:35 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 09:25 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.