QuakeIndex

Earthquake · reviewed by a seismologist

M 4.5mwr

84 km ESE of Sand Point, Alaska

Yes. A magnitude 4.5 earthquake was recorded 84 km ESE of Sand Point, Alaska, at 2:52 am AKST on 15 November 2017 (11:52 UTC), 32 km deep. 2 people have reported feeling it to USGS.

· 32 km deep · released about 85 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 4.5 (mwr)
Depth
32 km below the surface
Felt
2 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1191 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 136 km (85 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 85 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 2,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 89× the energy of this one
  3. Magna, Utah 2020 M 5.7 63× the energy of this one
  4. This earthquake M 4.5 about 85 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 180× 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 4.4 on 2017-02-13.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.4 54 km SE of Sand Point, Alaska · 42 km WSW of this epicentre
  2. 6.6 72 km SE of Sand Point, Alaska · 28 km SW of this epicentre
  3. 6.6 104 km SSE of Perryville, Alaska · 39 km E of this epicentre
  4. 6.6 85 km SE of Sand Point, Alaska · 43 km SSW of this epicentre
  5. 6.5 94 km ESE of Sand Point, Alaska · 18 km SSE 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 55.0847, -159.2482. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.2 66 km S of Ivanof Bay, Alaska
  2. 1.7 47 km E of Sand Point, Alaska
  3. 2.3 63 km ESE of Sand Point, Alaska
  4. 3.2 68 km ESE of Sand Point, Alaska
  5. 2.1 64 km ESE of Sand Point, Alaska
  6. 3.4 63 km ESE of Sand Point, Alaska
  7. 2.7 66 km SSE of Perryville, Alaska
  8. 2.0 65 km S of Ivanof Bay, Alaska
  9. 2.2 51 km S of Perryville, Alaska
  10. 3.2 101 km ESE of Sand Point, Alaska
  11. 2.5 63 km S of Ivanof Bay, Alaska
  12. 1.6 68 km ESE of Sand Point, Alaska
  13. 2.2 84 km ESE of Sand Point, Alaska
  14. 2.2 Alaska Peninsula
  15. 2.1 65 km ESE of Sand Point, 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.