QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Anchorage, AK

No earthquake was likely felt in Anchorage in the 24 hours to 1:50 am AKST (10:50 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

This page: a magnitude 1.7 earthquake was recorded 46 km (29 mi) southwest of Anchorage, AK, at 8:06 pm AKDT on 19 August 2021 (04:06 UTC), 10 km deep.

USGS: 10 km E of Point Possession, Alaska

46 km (29 mi) SW of Anchorage, AK

8:06 pm AKDT, Aug 19, 2021 · · 10 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 71 kmKenai Peninsula Borough 117 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
8:06 pm AKDT on 19 August 2021 ()
Where
46 km (29 mi) southwest of Anchorage, AK · earthquakes near Anchorage
Magnitude
M 1.7 (ml)
Depth
10 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 71 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1899 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 7 km (4 mi) from the epicentre. In Anchorage, 46 km away, the estimate is intensity I (not felt). 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 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 5.8 on 2018-11-30 — about 1,400,000 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 Southern Alaska · 39 km WNW of this epicentre
  2. 6.8 4 km NE of Beluga, Alaska · 40 km NW of this epicentre
  3. 6.8 24 km ENE of Sterling, Alaska · 30 km S of this epicentre
  4. 6.4 19 km SSE of Tyonek, Alaska · 30 km W of this epicentre
  5. 5.8 20 km ENE of Beluga, Alaska · 39 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 60.9176, -150.4887. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 71 km (44 mi) ENE earthquakes near Anchorage Municipality
Kenai Peninsula Borough, AK 117 km (73 mi) WSW earthquakes near Kenai Peninsula Borough

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

Aftershocks so far

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

  1. 2.0 8 km SE of Tyonek, Alaska
  2. 2.6 22 km E of Funny River, Alaska
  3. 1.5 14 km W of Point Possession, Alaska
  4. 1.5 27 km SSW of Susitna, Alaska
  5. 1.6 12 km WNW of Anchorage, Alaska
  6. 2.3 19 km SW of Point MacKenzie, Alaska
  7. 1.5 20 km SSE of Point Possession, Alaska
  8. 1.5 11 km SE of Point Possession, Alaska
  9. 1.8 7 km NNE of Sterling, Alaska
  10. 1.7 25 km SW of Anchorage, Alaska
  11. 2.3 7 km WSW of Anchorage, Alaska
  12. 2.2 23 km E of Beluga, Alaska
  13. 1.5 22 km NNE of Beluga, Alaska
  14. 1.5 6 km SSW of Point Possession, Alaska
  15. 1.5 7 km WNW of Point Possession, 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.