QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

Earthquake near Willow, AK

No earthquake was likely felt in Willow in the 24 hours to 2:46 am AKST (11:46 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 2.7 earthquake was recorded 17 km (11 mi) north of Willow, AK, at 11:27 am AKDT on 19 April 2021 (19:27 UTC), 9.1 km deep. 4 people have reported feeling it to USGS.

USGS: 16 km N of Willow, Alaska

76 km (47 mi) N of Anchorage, AK

11:27 am AKDT, Apr 19, 2021 · · 9.1 km deep · released about 340 lb of TNT

Every earthquake near Willow Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Matanuska-Susitna Borough 48 kmAnchorage Municipality 89 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
11:27 am AKDT on 19 April 2021 ()
Where
17 km (11 mi) north of Willow, AK · earthquakes near Willow
Magnitude
M 2.7 (ml)
Depth
9.1 km below the surface
Felt
4 reports · strongest reported intensity II
Nearest
Matanuska-Susitna Borough, 48 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1959 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 23 km (14 mi) from the epicentre. In Willow, 17 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.

Likely felt in: Willow 17 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.8× the energy of this one
  4. This earthquake M 2.7 about 340 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 5,600 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. 5.9 23 km NE of Willow, Alaska · 13 km E of this epicentre
  2. 5.8 14 km NNE of Fishhook, Alaska · 47 km E of this epicentre
  3. 5.6 11 km NW of Big Lake, Alaska · 36 km SSW of this epicentre
  4. 5.6 5 km N of Susitna, Alaska · 43 km SW of this epicentre
  5. 5.5 9 km E of Susitna, Alaska · 44 km SSW 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 61.8977, -149.9874. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Matanuska-Susitna Borough, AK 48 km (30 mi) NNE earthquakes near Matanuska-Susitna Borough
Anchorage Municipality, AK 89 km (55 mi) SSE 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. 2.3 8 km W of Willow, Alaska
  2. 2.6 8 km ENE of Susitna North, Alaska
  3. 1.5 11 km E of Willow, Alaska
  4. 1.7 16 km W of Willow, Alaska
  5. 3.3 15 km NE of Susitna North, Alaska
  6. 3.0 14 km NNE of Houston, Alaska
  7. 2.9 12 km N of Meadow Lakes, Alaska
  8. 2.1 20 km ESE of Susitna North, Alaska
  9. 3.4 13 km N of Susitna North, Alaska
  10. 1.5 28 km SSW of Trapper Creek, Alaska
  11. 1.8 4 km ESE of Big Lake, Alaska
  12. 1.8 8 km ENE of Big Lake, Alaska
  13. 1.5 19 km S of Trapper Creek, Alaska
  14. 1.5 21 km SSW of Trapper Creek, Alaska
  15. 1.8 1 km WNW of Wasilla, 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.