QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

Earthquake near Healy, AK

No earthquake was likely felt in Healy in the 24 hours to 5:58 am AKST (14:58 UTC). The last one was M 2.7, 23 km (14 mi) NNE, at 4:13 pm AKST on 3 November 2026, estimated intensity II (weak) in town. Every earthquake near Healy

This page: a magnitude 3.2 earthquake was recorded 7 km (4 mi) east of Healy, AK, at 6:39 am AKDT on 1 July 2021 (14:39 UTC), 111 km deep.

USGS: 6 km E of Healy, Alaska

6:39 am AKDT, Jul 1, 2021 · · 111 km deep · released about 1,900 lb of TNT

10 km30 km60 km120 km N Denali Borough 62 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
6:39 am AKDT on 1 July 2021 ()
Where
7 km (4 mi) east of Healy, AK · earthquakes near Healy
Magnitude
M 3.2 (ml)
Depth
111 km below the surface
Felt
no reports yet
Nearest
Denali Borough, 62 km WSW
Nearest mapped fault
Park Road fault (Northern Foothills fold and thrust belt), 11 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 1891 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 Healy, 7 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 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
  4. This earthquake M 3.2 about 1,900 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 2× 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 4.6 on 2018-01-19 — about 130 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 7.1 Central Alaska · 27 km NNE of this epicentre
  2. 6.4 23 km ENE of Ferry, Alaska · 30 km NNE of this epicentre
  3. 6.1 35 km E of Healy, Alaska · 29 km E of this epicentre
  4. 5.0 30 km W of Ferry, Alaska · 49 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 63.8510, -148.8255. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Denali Borough, AK 62 km (39 mi) WSW earthquakes near Denali Borough
Fairbanks North Star Borough, AK 145 km (90 mi) NE earthquakes near Fairbanks North Star Borough

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 18 km E of Ferry, Alaska
  2. 1.8 9 km NNE of Cantwell, Alaska
  3. 1.6 27 km ENE of Cantwell, Alaska
  4. 1.7 17 km WSW of Denali Park, Alaska
  5. 1.6 17 km E of Ferry, Alaska
  6. 1.7 14 km E of Healy, Alaska
  7. 1.6 17 km E of Ferry, Alaska
  8. 2.3 21 km ENE of Denali Park, Alaska
  9. 1.9 24 km ENE of Cantwell, Alaska
  10. 1.5 25 km ENE of Cantwell, Alaska
  11. 2.2 10 km WNW of Denali Park, Alaska
  12. 1.5 Central Alaska
  13. 1.6 21 km ENE of Denali Park, Alaska
  14. 2.1 31 km ENE of Cantwell, Alaska
  15. 2.3 9 km WSW of Healy, 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.