M3.1 Earthquake 30 km WSW of Birney, Montana — December 31, 2021
2021-12-31 19:35:54 UTC (2021-12-31) · approx. 12:35 PM UTC-7 local
On December 31, 2021 at 19:35 UTC, a magnitude 3.1 shallow crustal earthquake struck 30 km WSW of Birney, Montana, at a depth of 0.0 km and coordinates 45.1694°, -106.8409°.
Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 674 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 83 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-106.8409°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near Birney, Montana?
The magnitude 3.1 earthquake that struck 30 km WSW of Birney, Montana on December 31, 2021 at 19:35 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 3.1 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.1 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us7000g87m). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 31, 2021). M3.1 Earthquake 30 km WSW of Birney, Montana — December 31, 2021. Retrieved March 5, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000g87m/