QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

Earthquake near Willow, AK

No earthquake was likely felt in Willow in the 24 hours to 1:10 pm AKST (22:10 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 2.9 earthquake was recorded 8 km (5 mi) northwest of Willow, AK, at 5:49 pm AKDT on 6 September 2019 (01:49 UTC), 14 km deep. 3 people have reported feeling it to USGS.

USGS: 8 km NW of Willow, Alaska

65 km (41 mi) NNW of Anchorage, AK

5:49 pm AKDT, Sep 6, 2019 · · 14 km deep · released about 680 lb of TNT

Every earthquake near Willow Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Matanuska-Susitna Borough 63 kmAnchorage Municipality 83 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
5:49 pm AKDT on 6 September 2019 ()
Where
8 km (5 mi) northwest of Willow, AK · earthquakes near Willow
Magnitude
M 2.9 (ml)
Depth
14 km below the surface
Felt
3 reports · strongest reported intensity II
Measured shaking
intensity II (ShakeMap)
Nearest
Matanuska-Susitna Borough, 63 km NNE
Nearest mapped fault
Castle Mountain fault, 22 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 2539 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, people at rest would likely notice it out to about 29 km (18 mi) from the epicentre. In Willow, 8 km away, the estimate is intensity III (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.

Likely felt in: Willow 8 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.4× the energy of this one
  4. This earthquake M 2.9 about 680 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 5.2 on 2018-11-30 — about 2,800 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. 6.9 27 km SE of Skwentna, Alaska · 46 km W of this epicentre
  2. 5.9 23 km NE of Willow, Alaska · 26 km ENE of this epicentre
  3. 5.7 19 km E of Skwentna, Alaska · 50 km WNW of this epicentre
  4. 5.6 11 km NW of Big Lake, Alaska · 24 km S of this epicentre
  5. 5.6 5 km N of Susitna, Alaska · 28 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 61.7913, -150.1613. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 63 km (39 mi) NNE earthquakes near Matanuska-Susitna Borough
Anchorage Municipality, AK 83 km (52 mi) SE earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 2.0 22 km NNW of Susitna, Alaska
  2. 1.5 9 km SW of Big Lake, Alaska
  3. 2.3 3 km NNW of Big Lake, Alaska
  4. 1.6 11 km SSW of Trapper Creek, Alaska
  5. 2.3 1 km SE of Big Lake, Alaska
  6. 1.7 25 km SSE of Susitna North, Alaska
  7. 2.0 5 km W of Point MacKenzie, Alaska
  8. 1.6 0 km SW of Point MacKenzie, Alaska
  9. 1.6 7 km NNE of Point MacKenzie, Alaska
  10. 1.7 4 km W of Point MacKenzie, Alaska
  11. 1.8 6 km SSE of Big Lake, Alaska
  12. 1.5 5 km NW of Point MacKenzie, Alaska
  13. 1.5 3 km ESE of Big Lake, Alaska
  14. 1.6 9 km WSW of Willow, Alaska
  15. 2.2 6 km N 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.