200 km SE of Atka, Alaska

Yes. A magnitude 3.1 earthquake was recorded 200 km SE of Atka, Alaska at 07:42 UTC on 2020-09-17, 10 km deep.

2020-09-17 07:42 UTC · 10 km deep · released about 1,300 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: 2020-09-17 07:42 UTC
Magnitude: M 3.1 (ml)
Depth: 10 km below the surface
Felt: no reports yet
Nearest mapped fault: Alaska-Aleutian subduction zone, 19 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 2176 days ago · we first saw it 2176 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 41 km (25 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

Northridge, California 1994 M 6.7 250,000× the energy of this one
Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
Magna, Utah 2020 M 5.7 7,900× the energy of this one
This earthquake M 3.1 about 1,300 lb of TNT
Around the size people start to feel M 3.0 this one released 1.4× 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.

For this area

The largest earthquake within 50 km since 2016 was M 4.2 on 2016-11-20 — about 45 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

6.9 240 km SE of Atka, Alaska · 41 km ESE of this epicentre Jul 29, 1965
6.0 228 km ESE of Atka, Alaska · 38 km E of this epicentre May 18, 1957
6.0 233 km ESE of Atka, Alaska · 38 km E of this epicentre Feb 17, 1959
5.8 227 km ESE of Atka, Alaska · 37 km ENE of this epicentre Mar 10, 1936
5.8 220 km ESE of Atka, Alaska · 46 km NE of this epicentre Mar 28, 1957

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

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

2.8 202 km SE of Atka, Alaska 04:36 UTC
3.1 193 km SE of Atka, Alaska 04:59 UTC
3.2 172 km SE of Atka, Alaska 18:32 UTC
3.5 217 km ESE of Atka, Alaska 15:52 UTC
3.7 228 km SE of Atka, Alaska 18:31 UTC
3.3 215 km SE of Atka, Alaska 02:35 UTC
3.3 213 km SE of Atka, Alaska 06:03 UTC
3.7 195 km SE of Atka, Alaska 04:01 UTC
2.7 211 km SE of Atka, Alaska 09:54 UTC
3.6 212 km SE of Atka, Alaska 08:16 UTC
3.1 173 km ESE of Atka, Alaska 12:01 UTC
2.4 189 km SE of Atka, Alaska 09:29 UTC
3.1 169 km ESE of Atka, Alaska 05:02 UTC
3.3 179 km ESE of Atka, Alaska 04:59 UTC
2.9 168 km SE of Atka, Alaska 02:00 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 08:38 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.