QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

166 km WSW of Adak, Alaska

Yes. A magnitude 3.1 earthquake was recorded 166 km WSW of Adak, Alaska at 20:48 UTC on 2017-06-22, 17 km deep.

· 17 km deep · released about 1,300 lb 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 3.1 (ml)
Depth
17 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1194 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 38 km (24 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.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. 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 6.2 on 2017-05-08 — about 45,000 times the energy of this one.

Before 2016, the USGS record lists 252 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 162 km WSW of Adak, Alaska · 8 km N of this epicentre
  2. 7.2 207 km WSW of Adak, Alaska · 43 km W of this epicentre
  3. 7.0 148 km WSW of Adak, Alaska · 20 km E of this epicentre
  4. 6.9 203 km WSW of Adak, Alaska · 39 km W of this epicentre
  5. 6.9 151 km WSW of Adak, Alaska · 15 km ENE 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 51.3450, -178.8856. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.9 169 km W of Adak, Alaska
  2. 2.2 126 km WSW of Adak, Alaska
  3. 1.6 124 km WSW of Adak, Alaska
  4. 1.8 133 km WSW of Adak, Alaska
  5. 2.2 175 km WSW of Adak, Alaska
  6. 2.2 126 km WSW of Adak, Alaska
  7. 1.8 125 km WSW of Adak, Alaska
  8. 2.6 139 km WSW of Adak, Alaska
  9. 2.1 132 km W of Adak, Alaska
  10. 1.9 125 km WSW of Adak, Alaska
  11. 2.0 133 km W of Adak, Alaska
  12. 1.6 129 km W of Adak, Alaska
  13. 1.7 129 km W of Adak, Alaska
  14. 3.0 123 km WSW of Adak, Alaska
  15. 1.6 134 km W of Adak, 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.