QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Anchorage, AK

No earthquake was likely felt in Anchorage in the 24 hours to 11:30 pm AKST (08:30 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 1.6 earthquake was recorded 22 km (14 mi) north of Anchorage, AK, at 11:08 pm AKDT on 18 October 2017 (07:08 UTC), 50 km deep.

USGS: 7 km NNE of Point MacKenzie, Alaska

22 km (14 mi) N of Anchorage, AK

11:08 pm AKDT, Oct 18, 2017 · · 50 km deep · released about 7.6 lb of TNT

Every earthquake near Anchorage Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Anchorage Municipality 43 kmMatanuska-Susitna Borough 96 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
11:08 pm AKDT on 18 October 2017 ()
Where
22 km (14 mi) north of Anchorage, AK · earthquakes near Anchorage
Magnitude
M 1.6 (ml)
Depth
50 km below the surface
Felt
no reports yet
Nearest
Anchorage Municipality, 43 km SE
Nearest mapped fault
Castle Mountain fault, 19 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 1191 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Anchorage, 22 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.

Earthquakes near other towns within 30 km: Big Lake, Knik-Fairview, Eagle River, Elmendorf Air Force Base, Houston, Meadow Lakes.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 4.1 on 2016-07-21 — about 5,600 times the energy of this one.

Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.6 11 km NW of Big Lake, Alaska · 21 km NNW of this epicentre
  2. 5.6 5 km N of Susitna, Alaska · 38 km WNW of this epicentre
  3. 5.5 2 km ENE of Eagle River, Alaska · 23 km ESE of this epicentre
  4. 5.5 9 km E of Susitna, Alaska · 27 km WNW of this epicentre
  5. 5.5 26 km SSW of Anchorage, Alaska · 47 km SSW 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 61.4187, -149.9027. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Anchorage Municipality, AK 43 km (27 mi) SE earthquakes near Anchorage Municipality
Matanuska-Susitna Borough, AK 96 km (60 mi) NNE earthquakes near Matanuska-Susitna Borough

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. 2.4 5 km WSW of Big Lake, Alaska
  2. 1.9 3 km SSE of Houston, Alaska
  3. 1.5 2 km SE of Eagle River, Alaska
  4. 1.7 20 km WNW of Fishhook, Alaska
  5. 1.7 7 km WNW of Knik-Fairview, Alaska
  6. 1.6 10 km WSW of Big Lake, Alaska
  7. 1.6 10 km SSE of Anchorage, Alaska
  8. 1.5 14 km N of Meadow Lakes, Alaska
  9. 1.5 3 km ESE of Knik-Fairview, Alaska
  10. 2.1 21 km WSW of Anchorage, Alaska
  11. 2.9 17 km WNW of Fishhook, Alaska
  12. 1.6 12 km ENE of Willow, Alaska
  13. 1.6 25 km WSW of Anchorage, Alaska
  14. 1.5 13 km NNE of Susitna, Alaska
  15. 1.5 16 km SSE of Susitna, 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.