Earthquake · reviewed by a seismologist
M 1.6ml
Earthquake near Helena Valley West Central, MT
No earthquake was likely felt in Helena Valley West Central in the 24 hours to 7:09 am MST (14:09 UTC). The last one was M 1.5, 4 km (2 mi) SE, at 3:20 pm MDT on 18 May 2025, estimated intensity II (weak) in town. Every earthquake near Helena Valley West Central
This page: a magnitude 1.6 earthquake was recorded 43 km (27 mi) north-northeast of Helena Valley West Central, MT, at 3:57 am MDT on 28 April 2025 (09:57 UTC), 7.4 km deep.
USGS: 6 km SE of Craig, Montana
- When
- 3:57 am MDT on 28 April 2025 ()
- Where
- 43 km (27 mi) north-northeast of Helena Valley West Central, MT · earthquakes near Helena Valley West Central
- Montana today
- every earthquake in Montana in the last 24 hours
- Magnitude
- M 1.6 (ml)
- Depth
- 7.4 km below the surface
- Felt
- no reports yet
- Nearest
- Lewis and Clark County, 38 km WNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 562 days ago
Earthquake alerts for Helena Valley West Central, MT
Get a notification in this browser when USGS records an earthquake near Helena Valley West Central, MT. 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 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 Helena Valley West Central, 43 km away, the estimate is intensity I (not felt). 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 8.1 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 1,900,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
- Around the size people start to feel M 3.0 120× the energy of this one
- This earthquake M 1.6 about 8.1 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 2016-01-30 — about 12,000 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.9 2 km ENE of Helena, Montana · 49 km S of this epicentre
- 5.0 2 km ENE of Helena, Montana · 49 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 47.0333, -111.8937. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lewis and Clark County, MT | 38 km (24 mi) | WNW | earthquakes near Lewis and Clark County |
| Cascade County, MT | 52 km (32 mi) | NE | earthquakes near Cascade County |
| Powell County, MT | 82 km (51 mi) | WSW | earthquakes near Powell County |
| Broadwater County, MT | 84 km (52 mi) | SSE | earthquakes near Broadwater County |
| Meagher County, MT | 89 km (55 mi) | ESE | earthquakes near Meagher County |
| Teton County, MT | 92 km (57 mi) | NNW | earthquakes near Teton County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
14 earthquakes have been recorded within 50 km since this one.
- 0.8 10 km NW of Helena Valley Northwest, Montana
- 1.1 14 km NNE of Marysville, Montana
- 1.3 20 km NNE of Marysville, Montana
- 1.6 23 km SSE of Augusta, Montana
- 1.5 16 km NE of Helena Valley Northwest, Montana
- 1.6 14 km SSE of Craig, Montana
- 2.4 21 km SSE of Craig, Montana
- 2.0 32 km ENE of Helena Valley Northeast, Montana
- 2.0 20 km NNE of Helena Valley Northeast, Montana
- 1.5 31 km ENE of Helena Valley Northeast, Montana
- 2.0 19 km E of Lincoln, Montana
- 1.7 14 km NNW of Winston, Montana
- 1.6 18 km E of Lincoln, Montana
- 1.5 3 km SE of Helena Valley West Central, Montana
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.