QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Deltana, AK

USGS: 16 km SSW of Dry Creek, Alaska

2:29 pm AKDT, Mar 23, 2021 · · 3.4 km deep · released about 11 lb of TNT

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10 km30 km60 km120 km N Southeast Fairbanks Census Area 85 km
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
2:29 pm AKDT on 23 March 2021 ()
Where
47 km (29 mi) SSE of Deltana, AK · earthquakes near Deltana
Magnitude
M 1.7 (ml)
Depth
3.4 km below the surface
Felt
no reports yet
Nearest
Southeast Fairbanks Census Area, 85 km ENE
Nearest mapped fault
Dot ''T'' Johnson fault (Northern Foothills fold and thrust belt), 18 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 1995 days ago

A magnitude 1.7 earthquake was recorded 47 km (29 mi) SSE of Deltana, AK, at 2:29 pm AKDT on 23 March 2021 (22:29 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 89× the energy of this one
  4. This earthquake M 1.7 about 11 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 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.9 44 km WNW of Mentasta Lake, Alaska · 42 km SSE of this epicentre
  2. 5.7 31 km NNE of Paxson, Alaska · 35 km WSW of this epicentre
  3. 5.4 19 km NNE of Paxson, Alaska · 48 km SW of this epicentre
  4. 5.4 36 km NE of Paxson, Alaska · 28 km SW of this epicentre
  5. 5.2 32 km SW of Dry Creek, Alaska · 18 km SW 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 63.5074, -144.7453. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Southeast Fairbanks Census Area, AK 85 km (53 mi) ENE earthquakes near Southeast Fairbanks Census Area

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 1.5 41 km NW of Mentasta Lake, Alaska
  2. 2.0 42 km NW of Mentasta Lake, Alaska
  3. 1.8 43 km NW of Mentasta Lake, Alaska
  4. 1.6 45 km WNW of Mentasta Lake, Alaska
  5. 1.9 43 km NW of Mentasta Lake, Alaska
  6. 1.6 42 km NW of Mentasta Lake, Alaska
  7. 1.5 41 km ENE of Paxson, Alaska
  8. 2.0 39 km WNW of Mentasta Lake, Alaska
  9. 1.9 38 km NW of Mentasta Lake, Alaska
  10. 2.1 37 km WNW of Mentasta Lake, Alaska
  11. 1.7 32 km NE of Paxson, Alaska
  12. 1.7 31 km NE of Paxson, Alaska
  13. 1.8 33 km NE of Paxson, Alaska
  14. 1.5 38 km SW of Dry Creek, Alaska
  15. 2.6 28 km ENE 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.