43 km WNW of Akhiok, Alaska

2021-05-27 22:51 UTC · 63 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: 2021-05-27 22:51 UTC
Magnitude: M 3.3 (ml)
Depth: 63 km below the surface
Felt: no reports yet
Nearest: Kodiak Island Borough, 83 km NE
Status: Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS 1883 days ago · we first saw it 1883 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

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.

Where

Map loads when it scrolls into view

Epicentre 57.1325, -154.8047. Map © OpenStreetMap contributors.

Nearby places

Place	Distance	Direction
Kodiak Island Borough, AK	83 km (51 mi)	SW of here	earthquakes near Kodiak Island Borough
Lake and Peninsula Borough, AK	145 km (90 mi)	SE of here	earthquakes near Lake and Peninsula Borough

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

1.6 35 km W of Akhiok, Alaska 20:47 UTC
1.7 21 km SSE of Karluk, Alaska 06:04 UTC
1.8 28 km SSW of Karluk, Alaska 08:39 UTC
2.0 73 km WNW of Akhiok, Alaska 23:43 UTC
1.7 42 km WNW of Akhiok, Alaska 21:59 UTC
2.0 70 km WNW of Akhiok, Alaska 17:52 UTC
2.1 24 km WSW of Karluk, Alaska 12:29 UTC
1.6 Kodiak Island region, Alaska 16:14 UTC
1.6 12 km WSW of Akhiok, Alaska 00:10 UTC
2.2 32 km SW of Akhiok, Alaska 06:54 UTC
1.6 46 km SSW of Karluk, Alaska 09:49 UTC
1.6 45 km W of Akhiok, Alaska 00:34 UTC
2.0 55 km WNW of Akhiok, Alaska 12:43 UTC
1.9 32 km SSW of Karluk, Alaska 14:10 UTC
2.0 Kodiak Island region, Alaska 06:22 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 09:35 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 5.3 on 2021-02-13 — it released about 1,000 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.