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 7:49 am AKST (16:49 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) west of Anchorage, AK, at 5:28 pm AKDT on 31 July 2023 (01:28 UTC), 9.6 km deep.

USGS: Southern Alaska

46 km (29 mi) W of Anchorage, AK

5:28 pm AKDT, Jul 31, 2023 · · 9.6 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 79 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
5:28 pm AKDT on 31 July 2023 ()
Where
46 km (29 mi) west of Anchorage, AK · earthquakes near Anchorage
Magnitude
M 1.7 (ml)
Depth
9.6 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 79 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1190 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 8 km (5 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 4.8 on 2022-07-12 — about 45,000 times the energy of this one.

Before 2016, the USGS record lists 22 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 Southern Alaska · 20 km WSW of this epicentre
  2. 6.8 4 km NE of Beluga, Alaska · 15 km WNW of this epicentre
  3. 6.4 19 km SSE of Tyonek, Alaska · 32 km SSW of this epicentre
  4. 5.8 17 km NW of Beluga, Alaska · 34 km WNW of this epicentre
  5. 5.8 27 km N of Beluga, Alaska · 31 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 61.1428, -150.7477. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 79 km (49 mi) E earthquakes near Anchorage Municipality
Kenai Peninsula Borough, AK 122 km (75 mi) SW earthquakes near Kenai Peninsula Borough

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

Aftershocks so far

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

  1. 1.5 14 km SSE of Point Possession, Alaska
  2. 1.8 Kenai Peninsula, Alaska
  3. 1.5 6 km WSW of Susitna, Alaska
  4. 2.0 6 km NW of Susitna, Alaska
  5. 2.0 22 km WSW of Point MacKenzie, Alaska
  6. 1.6 6 km S of Tyonek, Alaska
  7. 1.7 6 km SSE of Tyonek, Alaska
  8. 1.6 11 km NW of Beluga, Alaska
  9. 1.5 23 km NE of Point Possession, Alaska
  10. 1.5 20 km SSW of Point Possession, Alaska
  11. 1.5 10 km SSE of Point Possession, Alaska
  12. 1.8 22 km WSW of Susitna, Alaska
  13. 1.5 26 km NNW of Beluga, Alaska
  14. 1.7 29 km N of Beluga, Alaska
  15. 2.3 19 km SSE 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.