Earthquake · reviewed by a seismologist
M 1.5ml
25 km W of Anderson, Alaska
Yes. A magnitude 1.5 earthquake was recorded 25 km W of Anderson, Alaska, at 3:08 pm AKST on 22 December 2020 (00:08 UTC), 8.2 km deep.
- When
- Magnitude
- M 1.5 (ml)
- Depth
- 8.2 km below the surface
- Felt
- no reports yet
- Nearest
- Denali Borough, 74 km SSW
- Nearest mapped fault
- Northern Foothills thrust fault (Northern Foothills fold and thrust belt), 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 2139 days ago
Earthquake alerts for Healy, AK
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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 minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 6 km (4 mi) from the epicentre. 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
- Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
- Around the size people start to feel M 3.0 180× the energy of this one
- This earthquake M 1.5 about 5.4 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 4.3 on 2016-12-08 — about 16,000 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.0 30 km W of Ferry, Alaska · 33 km S 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 64.3301, -149.7134. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Denali Borough, AK | 74 km (46 mi) | SSW | earthquakes near Denali Borough |
| Yukon-Koyukuk Census Area, AK | 146 km (91 mi) | NW | earthquakes near Yukon-Koyukuk Census Area |
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.
- 1.6 31 km W of Clear, Alaska, Alaska
- 1.5 15 km SSW of Clear, Alaska, Alaska
- 1.6 30 km W of Clear, Alaska, Alaska
- 1.6 11 km NNW of Four Mile Road, Alaska
- 1.6 27 km W of Four Mile Road, Alaska
- 2.6 30 km WNW of Four Mile Road, Alaska
- 1.5 28 km W of Anderson, Alaska
- 1.7 14 km NW of Four Mile Road, Alaska
- 1.6 42 km WSW of Clear, Alaska, Alaska
- 2.9 39 km WSW of Clear, Alaska, Alaska
- 1.6 20 km WSW of Ferry, Alaska
- 1.5 12 km NNW of Four Mile Road, Alaska
- 2.2 25 km WSW of Clear, Alaska, Alaska
- 2.6 24 km W of Ferry, Alaska
- 1.7 13 km NW of Four Mile Road, 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.