98 km SE of Ugashik, Alaska

2021-10-04 11:06 UTC · 59 km deep · released about 30 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: 2021-10-04 11:06 UTC
Magnitude: M 2.0 (ml)
Depth: 59 km below the surface
Felt: no reports yet
Status: Reviewed by a seismologist

USGS · last changed by USGS 1752 days ago · we first saw it 1752 days ago

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

How big was it?

This earthquake released about 30 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 500,000× the energy of this one
Magna, Utah 2020 M 5.7 350,000× the energy of this one
Around the size people start to feel M 3.0 32× the energy of this one
This earthquake M 2.0 about 30 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.

Where

Map loads when it scrolls into view

Epicentre 56.8660, -156.2973. Map © OpenStreetMap contributors.

Aftershocks so far

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

2.2 123 km E of Chignik, Alaska 21:39 UTC
1.5 100 km ESE of Ugashik, Alaska 15:24 UTC
1.6 70 km ESE of Ugashik, Alaska 03:04 UTC
1.5 67 km ESE of Ugashik, Alaska 15:54 UTC
2.1 128 km WSW of Akhiok, Alaska 14:28 UTC
2.0 124 km SSE of Ugashik, Alaska 07:18 UTC
2.6 Alaska Peninsula 04:42 UTC
2.5 97 km ESE of Ugashik, Alaska 08:50 UTC
2.0 103 km W of Akhiok, Alaska 23:47 UTC
2.4 114 km SSE of Ugashik, Alaska 13:40 UTC
2.7 80 km ESE of Ugashik, Alaska 10:23 UTC
2.0 88 km SE of Ugashik, Alaska 05:55 UTC
2.3 53 km SE of Ugashik, Alaska 01:03 UTC
2.8 Alaska Peninsula 15:10 UTC
2.7 124 km WSW of Akhiok, Alaska 18:41 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 10:19 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 4.5 on 2016-02-14 — it released about 5,600 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.