M3.2 Earthquake 19 km N of Colstrip, Montana — October 21, 2025
2025-10-21 20:39:20 UTC (2025-10-21) · approx. 1:39 PM UTC-7 local
On October 21, 2025 at 20:39 UTC, a magnitude 3.2 shallow crustal earthquake struck 19 km N of Colstrip, Montana, at a depth of 0.0 km and coordinates 46.0549°, -106.6434°.
Physical scale: An earthquake of magnitude 3.2 releases seismic energy equivalent to roughly 951 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 97 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-106.6434°E
Technical Information
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Common Questions
How strong was the magnitude 3.2 earthquake near Colstrip, Montana?
The magnitude 3.2 earthquake that struck 19 km N of Colstrip, Montana on October 21, 2025 at 20:39 UTC had a depth of 0.0 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.2 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.2 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000rija). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, October 21, 2025). M3.2 Earthquake 19 km N of Colstrip, Montana — October 21, 2025. Retrieved January 9, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rija/