QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

49 km NNW of Paxson, Alaska

Yes. A magnitude 2.9 earthquake was recorded 49 km NNW of Paxson, Alaska, at 7:39 pm AKST on 6 December 2018 (04:39 UTC), 1.3 km deep. 1 person has reported feeling it to USGS.

· 1.3 km deep · released about 680 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 2.9 (ml)
Depth
1.3 km below the surface
Felt
1 report · strongest reported intensity II
Nearest mapped fault
Denali fault, 4 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1184 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 32 km (20 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 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.4× the energy of this one
  4. This earthquake M 2.9 about 680 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 30 km SSW of Fort Greely, Alaska · 27 km NNE of this epicentre
  2. 5.7 31 km NNE of Paxson, Alaska · 39 km ESE of this epicentre
  3. 5.6 23 km NNW of Paxson, Alaska · 28 km SE of this epicentre
  4. 5.6 23 km N of Paxson, Alaska · 28 km SE of this epicentre
  5. 5.4 19 km NNE of Paxson, Alaska · 38 km SE 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 63.4818, -146.0771. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.8 29 km N of Paxson, Alaska
  2. 1.5 27 km N of Paxson, Alaska
  3. 1.5 45 km NNW of Paxson, Alaska
  4. 1.8 41 km NNW of Paxson, Alaska
  5. 1.8 45 km WSW of Delta Junction, Alaska
  6. 1.9 10 km SSW of Fort Greely, Alaska
  7. 2.2 6 km SSW of Fort Greely, Alaska
  8. 1.5 49 km SSW of Fort Greely, Alaska
  9. 1.8 52 km NNW of Paxson, Alaska
  10. 2.5 49 km SSW of Fort Greely, Alaska
  11. 1.6 29 km N of Paxson, Alaska
  12. 2.0 51 km NNW of Paxson, Alaska
  13. 1.7 23 km SW of Fort Greely, Alaska
  14. 1.5 Central Alaska
  15. 1.6 30 km N of Paxson, 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.