QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

Earthquake near Willow, AK

No earthquake was likely felt in Willow in the 24 hours to 5:20 am AKST (14:20 UTC). The last one was M 2.8, 20 km (12 mi) S, at 6:17 am AKST on 6 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Willow

This page: a magnitude 3.1 earthquake was recorded 34 km (21 mi) northwest of Willow, AK, at 6:04 am AKDT on 21 October 2019 (14:04 UTC), 60 km deep. 1 person has reported feeling it to USGS.

USGS: 34 km WSW of Susitna North, Alaska

91 km (57 mi) NNW of Anchorage, AK

6:04 am AKDT, Oct 21, 2019 · · 60 km deep · released about 1,300 lb of TNT

Every earthquake near Willow Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Matanuska-Susitna Borough 56 kmAnchorage Municipality 110 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
6:04 am AKDT on 21 October 2019 ()
Where
34 km (21 mi) northwest of Willow, AK · earthquakes near Willow
Magnitude
M 3.1 (ml)
Depth
60 km below the surface
Felt
1 report · strongest reported intensity II
Measured shaking
intensity II (ShakeMap)
Nearest
Matanuska-Susitna Borough, 56 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2506 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 Willow, 34 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× more

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 5.2 on 2019-09-17 — about 1,400 times the energy of this one.

Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 27 km SE of Skwentna, Alaska · 39 km WSW of this epicentre
  2. 5.9 23 km NE of Willow, Alaska · 37 km ESE of this epicentre
  3. 5.7 19 km E of Skwentna, Alaska · 32 km W of this epicentre
  4. 5.6 11 km NW of Big Lake, Alaska · 49 km SSE of this epicentre
  5. 5.6 5 km N of Susitna, Alaska · 45 km S 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 62.0009, -150.4115. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 56 km (35 mi) ENE earthquakes near Matanuska-Susitna Borough
Anchorage Municipality, AK 110 km (68 mi) SSE earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 1.6 26 km ENE of Skwentna, Alaska
  2. 1.5 1 km N of Susitna, Alaska
  3. 2.6 23 km WNW of Susitna, Alaska
  4. 1.6 26 km ESE of Skwentna, Alaska
  5. 3.0 16 km SSW of Willow, Alaska
  6. 1.6 11 km NNW of Big Lake, Alaska
  7. 1.5 15 km W of Trapper Creek, Alaska
  8. 2.4 15 km NNE of Willow, Alaska
  9. 1.8 33 km NNW of Susitna, Alaska
  10. 1.8 10 km NW of Susitna, Alaska
  11. 1.6 6 km SSW of Willow, Alaska
  12. 1.5 24 km NNW of Susitna, Alaska
  13. 1.6 30 km WNW of Willow, Alaska
  14. 1.7 12 km SSW of Trapper Creek, Alaska
  15. 1.8 23 km W of Willow, 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.