M3.2 Earthquake 7 km WSW of Colstrip, Montana — September 23, 2021
2021-09-23 20:13:18 UTC (2021-09-23) · approx. 1:13 PM UTC-7 local
On September 23, 2021 at 20:13 UTC, a magnitude 3.2 shallow crustal earthquake struck 7 km WSW of Colstrip, Montana, at a depth of 0.0 km and coordinates 45.8470°, -106.7106°.
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
-106.7106°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 7 km WSW of Colstrip, Montana on September 23, 2021 at 20:13 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: us7000fdvv). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, September 23, 2021). M3.2 Earthquake 7 km WSW of Colstrip, Montana — September 23, 2021. Retrieved December 3, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000fdvv/