198 km SW of Adak, Alaska

Yes. A magnitude 4.7 earthquake was recorded 198 km SW of Adak, Alaska at 12:28 UTC on 2017-08-25, 24 km deep.

2017-08-25 12:28 UTC · 24 km deep · released about 170 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: 2017-08-25 12:28 UTC
Magnitude: M 4.7 (mb)
Depth: 24 km below the surface
Felt: no reports yet
Nearest mapped fault: Alaska-Aleutian subduction zone, 24 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 1193 days ago · we first saw it 1193 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 158 km (98 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 170 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.7 would have released about 32 times as much.

Northridge, California 1994 M 6.7 1,000× the energy of this one
Mineral, Virginia 2011 M 5.8 45× the energy of this one
Magna, Utah 2020 M 5.7 32× the energy of this one
This earthquake M 4.7 about 170 tons of TNT
Around the size people start to feel M 3.0 this one released 350× 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 (31 mi) since our catalogue begins in 2016. No other earthquake of M4 or more has been recorded this close in that time.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

6.3 200 km SW of Adak, Alaska · 22 km NW of this epicentre Oct 28, 1920
6.2 161 km SW of Adak, Alaska · 40 km NNE of this epicentre Dec 9, 1918
6.0 207 km SW of Adak, Alaska · 10 km SSW of this epicentre Feb 7, 1926
5.0 156 km SW of Adak, Alaska · 46 km NNE of this epicentre May 22, 2011

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

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

2.2 177 km SW of Adak, Alaska 08:48 UTC
2.1 203 km SW of Adak, Alaska 21:13 UTC
3.7 208 km SW of Adak, Alaska 09:57 UTC
2.6 217 km SSW of Adak, Alaska 18:02 UTC
3.2 157 km SW of Adak, Alaska 13:17 UTC
1.9 211 km SSW of Adak, Alaska 11:59 UTC
3.0 194 km SSW of Adak, Alaska 10:03 UTC
2.6 151 km SW of Adak, Alaska 17:07 UTC
2.7 163 km SW of Adak, Alaska 08:58 UTC
1.9 191 km SW of Adak, AK 01:04 UTC
2.0 207 km SW of Adak, Alaska 19:19 UTC
4.3 222 km SW of Adak, Alaska 13:47 UTC
4.0 149 km SW of Adak, Alaska 14:49 UTC
3.6 206 km SW of Adak, Alaska 00:52 UTC
2.1 212 km SSW of Adak, Alaska 08:33 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 08:24 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.