QuakeIndex

Earthquake · reviewed by a seismologist

M 5.2mww

Earthquake near Willow, AK

No earthquake was likely felt in Willow in the 24 hours to 1:30 pm AKST (22:30 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 5.2 earthquake was recorded 45 km (28 mi) west of Willow, AK, at 5:09 pm AKDT on 16 September 2019 (01:09 UTC), 63 km deep. 1,174 people have reported feeling it to USGS.

USGS: 28 km NW of Susitna, Alaska

77 km (48 mi) NW of Anchorage, AK

5:09 pm AKDT, Sep 16, 2019 · · 63 km deep · released about 950 tons of TNT

Every earthquake near Willow Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Matanuska-Susitna Borough 94 kmAnchorage Municipality 105 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
5:09 pm AKDT on 16 September 2019 ()
Where
45 km (28 mi) west of Willow, AK · earthquakes near Willow
Magnitude
M 5.2 (mww)
Depth
63 km below the surface
Felt
1,174 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Matanuska-Susitna Borough, 94 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 325 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

At this magnitude and depth, people at rest would likely notice it out to about 209 km (130 mi) from the epicentre. In Willow, 45 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 45 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 950 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7.9× the energy of this one
  3. Magna, Utah 2020 M 5.7 5.6× the energy of this one
  4. This earthquake M 5.2 about 950 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2,000× 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 (31 mi) since our catalogue begins in 2016. The previous largest was M 4.5 on 2016-01-18.

Before 2016, the USGS record lists 21 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 27 km SE of Skwentna, Alaska · 12 km NW of this epicentre
  2. 5.8 27 km N of Beluga, Alaska · 37 km SSW of this epicentre
  3. 5.7 19 km E of Skwentna, Alaska · 30 km NNW of this epicentre
  4. 5.6 11 km NW of Big Lake, Alaska · 43 km ESE of this epicentre
  5. 5.6 5 km N of Susitna, Alaska · 24 km SE 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 61.7197, -150.8904. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 94 km (59 mi) NE earthquakes near Matanuska-Susitna Borough
Anchorage Municipality, AK 105 km (65 mi) SE earthquakes near Anchorage Municipality

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

Aftershocks so far

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

  1. 1.7 27 km SSE of Skwentna, Alaska
  2. 1.6 7 km S of Susitna, Alaska
  3. 1.7 37 km NW of Willow, Alaska
  4. 1.7 26 km SSW of Susitna, Alaska
  5. 1.5 5 km WNW of Susitna, Alaska
  6. 1.6 14 km NNE of Susitna, Alaska
  7. 2.6 27 km SSW of Susitna, Alaska
  8. 1.9 6 km WSW of Susitna, Alaska
  9. 1.8 27 km WNW of Susitna, Alaska
  10. 2.4 Southern Alaska
  11. 2.0 33 km ENE of Skwentna, Alaska
  12. 1.5 25 km WNW of Susitna, Alaska
  13. 2.4 38 km W of Susitna, Alaska
  14. 1.6 9 km ESE of Skwentna, Alaska
  15. 1.9 29 km N of Beluga, 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.