Earthquake · reviewed by a seismologist
M 1.6ml
Earthquake near Willow, AK
No earthquake was likely felt in Willow in the 24 hours to 5:29 am AKST (14:29 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 1.6 earthquake was recorded 19 km (12 mi) north of Willow, AK, at 5:56 am AKDT on 23 August 2023 (13:56 UTC), 6.9 km deep.
USGS: 18 km N of Willow, Alaska
78 km (48 mi) N of Anchorage, AK
- When
- 5:56 am AKDT on 23 August 2023 ()
- Where
- 19 km (12 mi) north of Willow, AK · earthquakes near Willow
- Magnitude
- M 1.6 (ml)
- Depth
- 6.9 km below the surface
- Felt
- no reports yet
- Nearest
- Matanuska-Susitna Borough, 50 km NE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1162 days ago
Earthquake alerts for Willow, 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 9 km (6 mi) from the epicentre. In Willow, 19 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 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
- Around the size people start to feel M 3.0 130× the energy of this one
- This earthquake M 1.6 about 7.6 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 5.1 on 2020-11-07 — about 180,000 times the energy of this one.
Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 27 km SE of Skwentna, Alaska · 50 km WSW of this epicentre
- 5.9 23 km NE of Willow, Alaska · 19 km E of this epicentre
- 5.7 19 km E of Skwentna, Alaska · 49 km W of this epicentre
- 5.6 11 km NW of Big Lake, Alaska · 37 km S of this epicentre
- 5.6 5 km N of Susitna, Alaska · 41 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 61.9125, -150.1029. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Matanuska-Susitna Borough, AK | 50 km (31 mi) | NE | earthquakes near Matanuska-Susitna Borough |
| Anchorage Municipality, AK | 93 km (58 mi) | SSE | earthquakes near Anchorage Municipality |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
58 earthquakes have been recorded within 50 km since this one.
- 1.5 7 km E of Big Lake, Alaska
- 1.5 6 km N of Knik, Alaska
- 1.7 15 km N of Susitna, Alaska
- 1.6 6 km ENE of Big Lake, Alaska
- 1.7 15 km NNE of Susitna, Alaska
- 1.5 16 km SW of Willow, Alaska
- 2.0 6 km NW of Susitna, Alaska
- 1.6 14 km ENE of Susitna, Alaska
- 1.8 3 km E of Big Lake, Alaska
- 1.8 1 km SE of Big Lake, Alaska
- 1.9 4 km SE of Big Lake, Alaska
- 1.9 3 km S of Houston, Alaska
- 2.1 16 km E of Willow, Alaska
- 2.0 11 km NE of Susitna, Alaska
- 1.8 8 km ENE of Susitna, 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.