Earthquake · reviewed by a seismologist
M 2.9ml
Earthquake near Healy, AK
No earthquake was likely felt in Healy in the 24 hours to 2:40 pm AKST (23:40 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 2.9 earthquake was recorded 35 km (22 mi) south-southwest of Healy, AK, at 12:09 am AKST on 8 November 2021 (09:09 UTC), 5.8 km deep. 2 people have reported feeling it to USGS.
USGS: 21 km NNW of Cantwell, Alaska
- When
- 12:09 am AKST on 8 November 2021 ()
- Where
- 35 km (22 mi) south-southwest of Healy, AK · earthquakes near Healy
- Magnitude
- M 2.9 (ml)
- Depth
- 5.8 km below the surface
- Felt
- 2 reports · strongest reported intensity III
- Nearest
- Denali Borough, 44 km WNW
- Nearest mapped fault
- Denali fault, 15 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 1763 days ago
Earthquake alerts for Healy, AK
Get a notification in this browser when USGS records an earthquake near Healy, AK. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 31 km (19 mi) from the epicentre. In Healy, 35 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 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.
- Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
- Magna, Utah 2020 M 5.7 16,000× the energy of this one
- Around the size people start to feel M 3.0 1.4× the energy of this one
- 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 4.6 on 2018-01-19 — about 350 times the energy of this one.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 5.1 50 km W of Cantwell, Alaska · 43 km WSW of this epicentre
- 5.1 36 km ENE of Cantwell, Alaska · 48 km E of this epicentre
- 5.0 41 km SW of Cantwell, Alaska · 49 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 63.5534, -149.1864. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Denali Borough, AK | 44 km (27 mi) | WNW | earthquakes near Denali Borough |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 1.7 13 km NNE of Healy, Alaska
- 1.7 11 km E of Healy, Alaska
- 1.5 34 km WNW of Cantwell, Alaska
- 2.9 0 km ESE of Cantwell, Alaska
- 1.9 15 km W of Healy, Alaska
- 2.1 20 km W of Denali Park, Alaska
- 1.6 30 km W of Cantwell, Alaska
- 2.1 28 km W of Denali Park, Alaska
- 1.5 Central Alaska
- 1.6 23 km SSW of Cantwell, Alaska
- 2.1 16 km NE of Cantwell, Alaska
- 1.6 38 km WSW of Denali Park, Alaska
- 1.5 10 km WNW of Denali Park, Alaska
- 1.5 15 km NNW of Cantwell, Alaska
- 3.0 19 km NNE of Cantwell, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.