QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Fishhook, AK

No earthquake was likely felt in Fishhook in the 24 hours to 10:07 am AKST (19:07 UTC). The last one was M 4.4, 118 km (73 mi) E, at 11:11 am AKDT on 30 October 2026, estimated intensity II (weak) in town; 54 felt reports to USGS. Every earthquake near Fishhook

This page: a magnitude 1.8 earthquake was recorded 18 km (11 mi) north of Fishhook, AK, at 11:23 pm AKDT on 20 October 2017 (07:23 UTC), 1.7 km deep.

USGS: 18 km N of Fishhook, Alaska

83 km (51 mi) NNE of Anchorage, AK

11:23 pm AKDT, Oct 20, 2017 · · 1.7 km deep · released about 15 lb of TNT

Every earthquake near Fishhook Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Matanuska-Susitna Borough 41 kmAnchorage Municipality 81 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
11:23 pm AKDT on 20 October 2017 ()
Where
18 km (11 mi) north of Fishhook, AK · earthquakes near Fishhook
Magnitude
M 1.8 (ml)
Depth
1.7 km below the surface
Felt
no reports yet
Nearest
Matanuska-Susitna Borough, 41 km NNW
Nearest mapped fault
Castle Mountain fault, 21 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, people at rest would likely notice it out to about 13 km (8 mi) from the epicentre. In Fishhook, 18 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.

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 4.3 on 2017-08-21 — about 5,600 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.9 23 km NE of Willow, Alaska · 23 km W of this epicentre
  2. 5.8 37 km ENE of Susitna North, Alaska · 44 km N of this epicentre
  3. 5.8 14 km NNE of Fishhook, Alaska · 12 km ESE of this epicentre
  4. 5.4 25 km NNW of Willow, Alaska · 45 km W of this epicentre
  5. 5.3 3 km NNE of Houston, Alaska · 37 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 61.9053, -149.2983. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 41 km (26 mi) NNW earthquakes near Matanuska-Susitna Borough
Anchorage Municipality, AK 81 km (51 mi) S earthquakes near Anchorage Municipality

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. 1.9 20 km N of Meadow Lakes, Alaska
  2. 2.3 4 km S of Houston, Alaska
  3. 1.5 4 km NW of Tanaina, Alaska
  4. 1.8 12 km NNW of Sutton-Alpine, Alaska
  5. 1.9 3 km SSE of Houston, Alaska
  6. 1.6 33 km ESE of Susitna North, Alaska
  7. 1.7 20 km WNW of Fishhook, Alaska
  8. 1.5 34 km ENE of Susitna North, Alaska
  9. 1.6 27 km NNW of Sutton-Alpine, Alaska
  10. 1.8 42 km ENE of Susitna North, Alaska
  11. 1.9 16 km NW of Fishhook, Alaska
  12. 1.7 7 km WNW of Knik-Fairview, Alaska
  13. 1.5 27 km SE of Susitna North, Alaska
  14. 1.5 14 km N of Meadow Lakes, Alaska
  15. 1.5 3 km ESE of Knik-Fairview, 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.