Earthquake · automatic estimate, may change
M 2.5ml
7 km WSW of Willow, Alaska
59 km (37 mi) NNW of Anchorage, AK
- When
- Magnitude
- M 2.5 (ml)
- Depth
- 5.0 km below the surface
- Felt
- 3 reports · strongest reported intensity III
- Nearest
- Matanuska-Susitna Borough, 69 km NNE
- Nearest mapped fault
- Castle Mountain fault, 17 km from its surface trace — near is not the same as on
- Status
- Automatic — a machine’s first estimate, which may change
USGS · last changed by USGS · we first saw it 2 hours ago
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 3 people have reported feeling it to USGS.
How big was it?
This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
- Magna, Utah 2020 M 5.7 63,000× the energy of this one
- Around the size people start to feel M 3.0 5.6× the energy of this one
- This earthquake M 2.5 about 170 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 7,900,000 times the energy of this one.
Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 27 km SE of Skwentna, Alaska · 46 km W of this epicentre
- 5.9 23 km NE of Willow, Alaska · 30 km NE of this epicentre
- 5.6 11 km NW of Big Lake, Alaska · 17 km S of this epicentre
- 5.6 5 km N of Susitna, Alaska · 23 km SW of this epicentre
- 5.5 9 km E of Susitna, Alaska · 23 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 61.7330, -150.1760. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Matanuska-Susitna Borough, AK | 69 km (43 mi) | NNE | earthquakes near Matanuska-Susitna Borough |
| Anchorage Municipality, AK | 78 km (49 mi) | SE | earthquakes near Anchorage Municipality |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
No further earthquakes have been recorded within 50 km since this one.
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.
Revisions
USGS refines a solution as more stations report. Every change we have seen is listed here.
| What changed | From | To | When |
|---|---|---|---|
| felt reports | 1 | 3 | |
| reported intensity | not reported | 2.7 | |
| felt reports | not reported | 1 | |
| location | 7 km W of Willow, Alaska | 7 km WSW of Willow, Alaska | |
| latitude | 61.74 | 61.73 | |
| depth | 0.1 | 5 |
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.