QuakeIndex

Earthquake · reviewed by a seismologist

M 3.7ml

75 km N of Aleneva, Alaska

Yes. A magnitude 3.7 earthquake was recorded 75 km N of Aleneva, Alaska, at 5:00 pm AKDT on 28 June 2018 (01:00 UTC), 60 km deep. 1 person has reported feeling it to USGS.

· 60 km deep · released about 5.4 tons of TNT

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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 3.7 (ml)
Depth
60 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Kodiak Island Borough, 134 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1186 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 46 km (29 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 5.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 32,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,000× the energy of this one
  4. This earthquake M 3.7 about 5.4 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 11× 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 4.9 on 2016-04-29 — about 63 times the energy of this one.

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

  1. 6.0 61 km WSW of Nanwalek, Alaska · 47 km NNW of this epicentre
  2. 5.8 63 km WSW of Nanwalek, Alaska · 41 km NNW of this epicentre
  3. 5.6 35 km N of Aleneva, Alaska · 42 km SSW of this epicentre
  4. 5.5 73 km WSW of Nanwalek, Alaska · 36 km NNW of this epicentre
  5. 5.3 41 km SSW of Nanwalek, Alaska · 43 km NE 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 58.7241, -152.6846. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kodiak Island Borough, AK 134 km (84 mi) SSW earthquakes near Kodiak Island Borough

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

Aftershocks so far

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

  1. 2.1 44 km WSW of Nanwalek, Alaska
  2. 1.7 60 km N of Aleneva, Alaska
  3. 1.9 76 km SW of Nanwalek, Alaska
  4. 1.6 83 km WSW of Nanwalek, Alaska
  5. 2.4 70 km SW of Nanwalek, Alaska
  6. 2.4 56 km SW of Nanwalek, Alaska
  7. 1.7 65 km WSW of Nanwalek, Alaska
  8. 1.5 29 km N of Aleneva, Alaska
  9. 2.0 42 km SW of Nanwalek, Alaska
  10. 1.5 40 km NNE of Aleneva, Alaska
  11. 1.6 Kodiak Island region, Alaska
  12. 2.2 51 km SSW of Nanwalek, Alaska
  13. 1.8 80 km WSW of Nanwalek, Alaska
  14. 2.7 78 km SW of Nanwalek, Alaska
  15. 2.6 52 km NNW of Aleneva, 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.