Earthquake · reviewed by a seismologist
M 1.7ml
Earthquake near Willow, AK
No earthquake was likely felt in Willow in the 24 hours to 9:05 am AKST (18:05 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 1.7 earthquake was recorded 9 km (6 mi) south of Willow, AK, at 5:28 am AKDT on 13 August 2023 (13:28 UTC), 9.2 km deep.
USGS: 9 km S of Willow, Alaska
50 km (31 mi) N of Anchorage, AK
- When
- 5:28 am AKDT on 13 August 2023 ()
- Where
- 9 km (6 mi) south of Willow, AK · earthquakes near Willow
- Magnitude
- M 1.7 (ml)
- Depth
- 9.2 km below the surface
- Felt
- no reports yet
- Nearest
- Anchorage Municipality, 67 km SE
- Nearest mapped fault
- Castle Mountain fault, 6 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 1176 days ago
Earthquake alerts for Willow, AK
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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 8 km (5 mi) from the epicentre. In Willow, 9 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.
Earthquakes near other towns within 30 km: Houston, Big Lake, Meadow Lakes, Knik-Fairview.
How big was it?
This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
- Around the size people start to feel M 3.0 89× the energy of this one
- This earthquake M 1.7 about 11 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 7.1 on 2018-11-30 — about 130,000,000 times the energy of this one.
Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:
- 5.9 23 km NE of Willow, Alaska · 31 km NNE of this epicentre
- 5.6 11 km NW of Big Lake, Alaska · 11 km SSW of this epicentre
- 5.6 5 km N of Susitna, Alaska · 27 km WSW of this epicentre
- 5.5 2 km ENE of Eagle River, Alaska · 45 km SE of this epicentre
- 5.5 9 km E of Susitna, Alaska · 22 km SW 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 61.6640, -150.0144. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Anchorage Municipality, AK | 67 km (42 mi) | SE | earthquakes near Anchorage Municipality |
| Matanuska-Susitna Borough, AK | 72 km (45 mi) | NNE | earthquakes near Matanuska-Susitna Borough |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 1.6 6 km SSE of Houston, Alaska
- 1.5 18 km NE of Willow, Alaska
- 2.5 11 km S of Susitna North, Alaska
- 2.8 22 km SW of Susitna North, Alaska
- 3.3 21 km W of Willow, Alaska
- 1.9 4 km ESE of Willow, Alaska
- 1.5 8 km NE of Susitna, Alaska
- 1.8 8 km NE of Susitna, Alaska
- 1.6 25 km SE of Susitna North, Alaska
- 1.6 25 km WSW of Point MacKenzie, Alaska
- 1.6 4 km N of Big Lake, Alaska
- 1.5 Southern Alaska
- 1.6 7 km NE of Big Lake, Alaska
- 1.8 0 km ESE of Willow, Alaska
- 1.7 8 km NNW of Big Lake, 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.