112 km E of Chignik, Alaska

Yes. A magnitude 2.3 earthquake was recorded 112 km E of Chignik, Alaska at 07:20 UTC on 2021-10-18, 20 km deep.

2021-10-18 07:20 UTC · 20 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: 2021-10-18 07:20 UTC
Magnitude: M 2.3 (ml)
Depth: 20 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1802 days ago · we first saw it 1802 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 2 km (1 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 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.

For this area

The largest earthquake within 50 km since 2016 was M 6.9 on 2021-10-11 — about 7,900,000 times the energy of this one.

Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:

6.8 117 km SSE of Ugashik, Alaska · 30 km NNE of this epicentre May 29, 2015
6.4 77 km ESE of Chignik, Alaska · 43 km WSW of this epicentre Mar 24, 1972
6.4 104 km SSE of Ugashik, Alaska · 36 km NNW of this epicentre May 20, 1979
6.3 112 km E of Chignik, Alaska · 17 km S of this epicentre Feb 25, 1953
6.1 132 km E of Chignik, Alaska · 25 km SE of this epicentre Sep 13, 1911

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

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

2.4 122 km E of Chignik, Alaska 08:11 UTC
1.8 112 km E of Chignik, Alaska 06:28 UTC
2.2 103 km E of Chignik, Alaska 13:20 UTC
1.9 109 km E of Chignik, Alaska 10:48 UTC
2.5 80 km E of Chignik, Alaska 15:11 UTC
2.6 120 km E of Chignik, Alaska 06:21 UTC
2.2 Alaska Peninsula 07:48 UTC
2.3 113 km E of Chignik, Alaska 19:41 UTC
2.2 112 km E of Chignik, Alaska 13:25 UTC
1.9 116 km E of Chignik, Alaska 17:48 UTC
1.7 136 km E of Chignik, Alaska 06:54 UTC
1.8 118 km E of Chignik, Alaska 05:04 UTC
2.3 116 km E of Chignik, Alaska 22:46 UTC
3.1 112 km E of Chignik, Alaska 03:25 UTC
2.5 117 km E of Chignik, Alaska 23:22 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 23:31 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.