QuakeIndex

ice quake · reviewed by a seismologist

M 1.7ml

Earthquake near Anchorage, AK

No earthquake was likely felt in Anchorage in the 24 hours to 6:46 am AKST (15:46 UTC). The last one was M 3.5, 39 km (24 mi) SSW, at 4:48 pm AKDT on 27 October 2026, estimated intensity II (weak) in town; 98 felt reports to USGS. Every earthquake near Anchorage

No: USGS classifies this as a ice quake, not an earthquake. A magnitude 1.7 ice quake was recorded 30 km (19 mi) southeast of Anchorage, AK, at 3:47 am AKDT on 3 September 2020 (11:47 UTC), less than 1 km deep.

USGS: 14 km NNE of Hope, Alaska

30 km (19 mi) SE of Anchorage, AK

3:47 am AKDT, Sep 3, 2020 · · 0.0 km deep · released about 11 lb of TNT

Every earthquake near Anchorage Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 20 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
3:47 am AKDT on 3 September 2020 ()
Where
30 km (19 mi) southeast of Anchorage, AK · earthquakes near Anchorage
Magnitude
M 1.7 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 20 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2250 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 12 km (7 mi) from the epicentre. In Anchorage, 30 km away, the estimate is intensity II (weak). 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.

Earthquakes near other towns within 30 km: Girdwood, Elmendorf Air Force Base.

USGS catalogues this as ice quake, not an earthquake.

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

The largest earthquake within 50 km since 2016 was M 7.1 on 2018-11-30 — about 130,000,000 times the energy of this one.

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

  1. 6.0 21 km N of Whittier, Alaska · 44 km E of this epicentre
  2. 5.7 13 km S of Girdwood, Alaska · 29 km SE of this epicentre
  3. 5.6 17 km W of Whittier, Alaska · 41 km SE of this epicentre
  4. 5.5 2 km ENE of Eagle River, Alaska · 34 km N of this epicentre
  5. 5.5 26 km SSW of Anchorage, Alaska · 33 km W 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 61.0242, -149.5036. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 20 km (13 mi) NE earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 1.8 5 km W of Elmendorf Air Force Base, Alaska
  2. 1.9 17 km N of Moose Pass, Alaska
  3. 1.9 3 km NNW of Anchorage, Alaska
  4. 1.9 2 km SSW of Point MacKenzie, Alaska
  5. 2.1 9 km NNE of Sunrise, Alaska
  6. 2.9 14 km N of Hope, Alaska
  7. 2.1 14 km SE of Knik-Fairview, Alaska
  8. 1.5 20 km WSW of Hope, Alaska
  9. 1.8 6 km NNE of Point MacKenzie, Alaska
  10. 2.2 8 km WNW of Eagle River, Alaska
  11. 1.6 4 km SW of Knik, Alaska
  12. 1.6 Southern Alaska
  13. 1.5 18 km SSE of Elmendorf Air Force Base, Alaska
  14. 1.6 6 km SW of Anchorage, Alaska
  15. 1.5 4 km NNW of Point MacKenzie, 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.