QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

123 km SSE of Sand Point, Alaska

Yes. A magnitude 2.7 earthquake was recorded 123 km SSE of Sand Point, Alaska, at 6:56 pm AKDT on 20 October 2020 (02:56 UTC), 29 km deep.

· 29 km deep · released about 340 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 2.7 (ml)
Depth
29 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2134 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 it was probably too small to be felt, even directly above it. 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 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.8× the energy of this one
  4. This earthquake M 2.7 about 340 lb of TNT

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 7.6 on 2020-10-19 — about 22,000,000 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 6.6 85 km SE of Sand Point, Alaska · 45 km N of this epicentre
  2. 6.1 79 km SE of Sand Point, Alaska · 46 km NNW of this epicentre
  3. 5.9 113 km SE of Sand Point, Alaska · 36 km NE of this epicentre
  4. 5.9 99 km SE of Sand Point, Alaska · 31 km N of this epicentre
  5. 5.4 75 km SSE of Sand Point, Alaska · 49 km NNW 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 54.3612, -159.5689. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.9 108 km SSE of Sand Point, Alaska
  2. 4.3 146 km SSE of Sand Point, Alaska
  3. 2.6 127 km SSE of Sand Point, Alaska
  4. 3.0 149 km SSE of Sand Point, Alaska
  5. 2.8 88 km SE of Sand Point, Alaska
  6. 2.7 125 km SSE of Sand Point, Alaska
  7. 2.6 122 km SSE of Sand Point, Alaska
  8. 2.9 105 km SSE of Sand Point, AK
  9. 2.7 108 km SSE of Sand Point, Alaska
  10. 3.6 134 km SSE of Sand Point, Alaska
  11. 2.7 96 km SE of Sand Point, Alaska
  12. 3.7 152 km SSE of Sand Point, Alaska
  13. 3.2 102 km SSE of Sand Point, Alaska
  14. 2.8 99 km SE of Sand Point, Alaska
  15. 3.5 105 km SSE 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.