QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Helena Valley Northeast, MT

No earthquake was likely felt in Helena Valley Northeast in the 24 hours to 12:19 pm MST (19:19 UTC). The last one was M 2.7, 11 km (7 mi) SSW, at 3:38 pm MDT on 9 March 2025, estimated intensity III (weak) in town; 267 felt reports to USGS. Every earthquake near Helena Valley Northeast

This page: a magnitude 2.1 earthquake was recorded 23 km (14 mi) north-northeast of Helena Valley Northeast, MT, at 11:07 pm MST on 24 February 2025 (06:07 UTC), 4.0 km deep.

USGS: 22 km NNE of Helena Valley Northeast, Montana

11:07 pm MST, Feb 24, 2025 · · 4.0 km deep · released about 40 lb of TNT

10 km30 km60 km120 km N Lewis and Clark County 50 kmCascade County 60 kmBroadwater County 66 kmMeagher County 76 kmPowell County 85 kmJefferson County 86 kmTeton County 110 kmJudith Basin County 116 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
11:07 pm MST on 24 February 2025 ()
Where
23 km (14 mi) north-northeast of Helena Valley Northeast, MT · earthquakes near Helena Valley Northeast
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.1 (ml)
Depth
4.0 km below the surface
Felt
no reports yet
Nearest
Lewis and Clark County, 50 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 624 days ago

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 16 km (10 mi) from the epicentre. In Helena Valley Northeast, 23 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: Helena Valley Northwest.

How big was it?

This earthquake released about 40 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.1 The 1935 Helena, Montana Earthquakes (Mainshock) · 35 km SSE of this epicentre
  2. 5.9 2 km ENE of Helena, Montana · 34 km SSW of this epicentre
  3. 5.9 The 1935 Helena, Montana Earthquakes (Largest Aftershock) · 38 km S of this epicentre
  4. 5.0 2 km ENE of Helena, Montana · 34 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 46.8818, -111.8188. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lewis and Clark County, MT 50 km (31 mi) WNW earthquakes near Lewis and Clark County
Cascade County, MT 60 km (37 mi) NE earthquakes near Cascade County
Broadwater County, MT 66 km (41 mi) SSE earthquakes near Broadwater County
Meagher County, MT 76 km (47 mi) ESE earthquakes near Meagher County
Powell County, MT 85 km (53 mi) W earthquakes near Powell County
Jefferson County, MT 86 km (54 mi) SSW earthquakes near Jefferson County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

23 earthquakes have been recorded within 50 km since this one.

  1. 0.8 10 km NW of Helena Valley Northwest, Montana
  2. 1.1 14 km NNE of Marysville, Montana
  3. 1.3 20 km NNE of Marysville, Montana
  4. 1.6 2 km SE of South Hills, Montana
  5. 1.5 16 km NE of Helena Valley Northwest, Montana
  6. 1.6 14 km SSE of Craig, Montana
  7. 2.4 21 km SSE of Craig, Montana
  8. 1.5 1 km SSE of South Hills, Montana
  9. 1.7 0 km NNW of South Hills, Montana
  10. 1.7 8 km S of Marysville, Montana
  11. 2.0 32 km ENE of Helena Valley Northeast, Montana
  12. 2.0 20 km NNE of Helena Valley Northeast, Montana
  13. 1.5 31 km ENE of Helena Valley Northeast, Montana
  14. 1.9 1 km SSE of South Hills, Montana
  15. 2.4 2 km ESE of Clancy, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.