128 km E of Chignik, Alaska

Yes. A magnitude 2.4 earthquake was recorded 128 km E of Chignik, Alaska at 23:09 UTC on 2019-09-20, 81 km deep.

2019-09-20 23:09 UTC · 81 km deep · released about 120 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: 2019-09-20 23:09 UTC
Magnitude: M 2.4 (ml)
Depth: 81 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 2529 days ago · we first saw it 2529 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 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
Magna, Utah 2020 M 5.7 89,000× the energy of this one
Around the size people start to feel M 3.0 7.9× the energy of this one
This earthquake M 2.4 about 120 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 4.5 on 2017-03-28 — about 1,400 times the energy of this one.

Before 2016, the USGS record lists 14 earthquakes of M5 or more within 50 km; the five largest:

6.8 117 km SSE of Ugashik, Alaska · 11 km NNW of this epicentre May 29, 2015
6.4 104 km SSE of Ugashik, Alaska · 27 km NW of this epicentre May 20, 1979
6.3 112 km E of Chignik, Alaska · 39 km SSW of this epicentre Feb 25, 1953
6.1 132 km E of Chignik, Alaska · 35 km S of this epicentre Sep 13, 1911
5.4 115 km SSE of Ugashik, Alaska · 15 km N of this epicentre Jun 9, 1971

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

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

1.8 92 km SSE of Ugashik, Alaska 07:14 UTC
3.2 111 km E of Chignik, Alaska 22:50 UTC
2.1 121 km ENE of Chignik, Alaska 05:31 UTC
2.2 103 km E of Chignik, Alaska 03:51 UTC
2.3 104 km SE of Ugashik, Alaska 19:12 UTC
2.4 130 km SW of Akhiok, Alaska 05:35 UTC
1.8 91 km SE of Ugashik, Alaska 18:09 UTC
2.1 113 km E of Chignik, Alaska 05:45 UTC
2.3 135 km E of Chignik, Alaska 16:07 UTC
2.0 115 km E of Chignik, Alaska 16:43 UTC
2.3 105 km W of Akhiok, Alaska 02:40 UTC
2.0 102 km SSE of Ugashik, Alaska 02:15 UTC
2.8 142 km E of Chignik, Alaska 03:06 UTC
2.6 92 km SSE of Ugashik, Alaska 08:59 UTC
2.1 135 km WSW of Akhiok, Alaska 09:33 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 21:08 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.