QuakeIndex

Earthquake · reviewed by a seismologist

M 5.0mw

39 km W of Karluk, Alaska

Yes. A magnitude 5.0 earthquake was recorded 39 km W of Karluk, Alaska at 17:59 UTC on 2017-04-27, 1.0 km deep.

· 1.0 km deep · released about 480 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Kodiak Island Borough 71 kmLake and Peninsula Borough 95 km
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
Magnitude
M 5.0 (mw)
Depth
1.0 km below the surface
Felt
no reports yet
Nearest
Kodiak Island Borough, 71 km E
Status
Reviewed by a seismologist

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

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

At this magnitude and depth, people at rest would likely notice it out to about 193 km (120 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 480 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 350× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 16× the energy of this one
  3. Magna, Utah 2020 M 5.7 11× the energy of this one
  4. This earthquake M 5.0 about 480 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 1,000× 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. The previous largest was M 4.3 on 2017-04-27.

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

  1. 7.1 4 km ENE of Karluk, Alaska · 43 km E of this epicentre
  2. 5.5 64 km SW of Karluk, Alaska · 47 km SSW of this epicentre
  3. 5.2 55 km WSW of Karluk, Alaska · 28 km SSW of this epicentre
  4. 5.0 54 km WNW of Karluk, Alaska · 18 km NW of this epicentre

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

Epicentre 57.6193, -155.1048. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kodiak Island Borough, AK 71 km (44 mi) E earthquakes near Kodiak Island Borough
Lake and Peninsula Borough, AK 95 km (59 mi) NW earthquakes near Lake and Peninsula Borough

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

Aftershocks so far

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

  1. 2.0 65 km WSW of Karluk, Alaska
  2. 1.9 55 km W of Karluk, Alaska
  3. 2.2 66 km WSW of Karluk, Alaska
  4. 1.5 70 km NW of Karluk, Alaska
  5. 2.3 59 km W of Karluk, Alaska
  6. 1.6 42 km W of Karluk, Alaska
  7. 2.0 30 km W of Karluk, Alaska
  8. 1.6 65 km WNW of Karluk, Alaska
  9. 2.1 30 km SW of Karluk, Alaska
  10. 1.7 35 km W of Karluk, Alaska
  11. 1.8 66 km WNW of Karluk, Alaska
  12. 1.8 49 km WSW of Karluk, Alaska
  13. 1.7 24 km WNW of Karluk, Alaska
  14. 1.9 68 km WSW of Karluk, Alaska
  15. 2.0 38 km WSW of Karluk, Alaska

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

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.