QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

Earthquake near Fishhook, AK

No earthquake was likely felt in Fishhook in the 24 hours to 5:00 pm AKST (02:00 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 2.5 earthquake was recorded 8 km (5 mi) west of Fishhook, AK, at 6:33 pm AKDT on 18 September 2020 (02:33 UTC), 28 km deep. 1 person has reported feeling it to USGS.

USGS: 7 km W of Fishhook, Alaska

64 km (40 mi) NNE of Anchorage, AK

6:33 pm AKDT, Sep 18, 2020 · · 28 km deep · released about 170 lb of TNT

Every earthquake near Fishhook Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Matanuska-Susitna Borough 59 kmAnchorage Municipality 63 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
6:33 pm AKDT on 18 September 2020 ()
Where
8 km (5 mi) west of Fishhook, AK · earthquakes near Fishhook
Magnitude
M 2.5 (ml)
Depth
28 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Matanuska-Susitna Borough, 59 km N
Nearest mapped fault
Castle Mountain fault, 5 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 2175 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Fishhook, 8 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: Tanaina, Lakes, Farm Loop, Meadow Lakes, Wasilla, Gateway.

How big was it?

This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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 4.7 on 2018-12-09 — about 2,000 times the energy of this one.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.9 23 km NE of Willow, Alaska · 26 km NW of this epicentre
  2. 5.8 14 km NNE of Fishhook, Alaska · 20 km NE of this epicentre
  3. 5.6 11 km NW of Big Lake, Alaska · 43 km WSW of this epicentre
  4. 5.5 2 km ENE of Eagle River, Alaska · 46 km S of this epicentre
  5. 5.4 25 km NNW of Willow, Alaska · 47 km WNW 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 61.7424, -149.3861. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 59 km (36 mi) N earthquakes near Matanuska-Susitna Borough
Anchorage Municipality, AK 63 km (39 mi) S earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 1.7 2 km ENE of Big Lake, Alaska
  2. 1.6 3 km NNE of Big Lake, Alaska
  3. 1.8 3 km NNE of Big Lake, Alaska
  4. 3.9 3 km ENE of Big Lake, Alaska
  5. 2.8 6 km NNE of Big Lake, Alaska
  6. 3.0 3 km NNE of Big Lake, Alaska
  7. 3.4 3 km NE of Big Lake, Alaska
  8. 5.1 2 km E of Big Lake, Alaska
  9. 2.5 4 km WNW of Knik-Fairview, Alaska
  10. 1.5 3 km WNW of Houston, AK
  11. 1.6 4 km SE of Knik, AK
  12. 1.9 5 km WNW of Houston, AK
  13. 1.8 21 km S of Fishhook, AK
  14. 2.2 9 km NNE of Point MacKenzie, Alaska
  15. 2.0 26 km NW of Fishhook, 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.