QuakeIndex

Earthquake · reviewed by a seismologist

M 5.6mww

246 km WSW of Adak, Alaska

Yes. A magnitude 5.6 earthquake was recorded 246 km WSW of Adak, Alaska at 03:57 UTC on 2020-01-26, 15 km deep.

· 15 km deep · released about 3.8 kilotons 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 5.6 (mww)
Depth
15 km below the surface
Felt
no reports yet
Measured shaking
intensity V (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 327 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 276 km (171 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 3.8 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 45× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2× the energy of this one
  3. Magna, Utah 2020 M 5.7 1.4× the energy of this one
  4. This earthquake M 5.6 about 3.8 kilotons of TNT
  5. Around the size people start to feel M 3.0 this one released 7,900× 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 5.1 on 2017-01-18.

Before 2016, the USGS record lists 93 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 238 km WSW of Adak, Alaska · 12 km NNE of this epicentre
  2. 7.2 207 km WSW of Adak, Alaska · 45 km NE of this epicentre
  3. 6.9 203 km WSW of Adak, Alaska · 48 km NE of this epicentre
  4. 6.9 231 km WSW of Adak, Alaska · 28 km N of this epicentre
  5. 6.8 235 km WSW of Adak, Alaska · 25 km N 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 51.0472, -179.9262. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.8 239 km WSW of Adak, Alaska
  2. 2.7 242 km WSW of Adak, Alaska
  3. 3.9 246 km WSW of Adak, Alaska
  4. 2.6 242 km WSW of Adak, Alaska
  5. 2.7 241 km WSW of Adak, Alaska
  6. 2.9 243 km WSW of Adak, Alaska
  7. 2.8 239 km WSW of Adak, Alaska
  8. 2.3 244 km WSW of Adak, Alaska
  9. 2.9 239 km WSW of Adak, Alaska
  10. 3.7 244 km WSW of Adak, Alaska
  11. 2.4 240 km WSW of Adak, Alaska
  12. 4.9 236 km WSW of Adak, Alaska
  13. 2.7 236 km WSW of Adak, Alaska
  14. 2.7 234 km WSW of Adak, Alaska
  15. 3.5 248 km WSW 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.