QuakeIndex

Earthquake · reviewed by a seismologist

M 5.0mww

240 km S of False Pass, Alaska

Yes. A magnitude 5.0 earthquake was recorded 240 km S of False Pass, Alaska at 22:07 UTC on 2016-10-01, 28 km deep. 6 people have reported feeling it to USGS.

· 28 km deep · released about 480 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 5.0 (mww)
Depth
28 km below the surface
Felt
6 reports · strongest reported intensity III
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 326 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 191 km (119 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. 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:

  1. 5.9 228 km S of False Pass, Alaska · 21 km WNW of this epicentre
  2. 5.6 203 km SSE of False Pass, Alaska · 46 km NNE of this epicentre
  3. 5.3 223 km S of False Pass, Alaska · 17 km NNW of this epicentre
  4. 5.0 240 km SSE of False Pass, Alaska · 43 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 52.7233, -162.8066. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.3 236 km SSE of False Pass, Alaska
  2. 3.8 260 km SE of Akutan, Alaska
  3. 2.2 191 km S of False Pass, Alaska
  4. 2.1 206 km S of False Pass, Alaska
  5. 3.6 238 km SE of Akutan, Alaska
  6. 2.2 224 km S of False Pass, Alaska
  7. 2.3 254 km S of False Pass, Alaska
  8. 2.9 201 km S of False Pass, Alaska
  9. 2.8 259 km SE of Akutan, Alaska
  10. 3.0 216 km S of False Pass, Alaska
  11. 2.7 224 km S of False Pass, Alaska
  12. 3.6 224 km S of False Pass, Alaska
  13. 2.9 227 km SSE of False Pass, Alaska
  14. 2.8 227 km SSE of False Pass, Alaska
  15. 2.4 240 km S of False Pass, 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.