M3.1 Earthquake 9 km NNW of Mountain Iron, Minnesota — December 8, 2020
2020-12-08 18:30:53 UTC (2020-12-08) · approx. 12:30 PM UTC-6 local
On December 8, 2020 at 18:30 UTC, a magnitude 3.1 shallow crustal earthquake struck 9 km NNW of Mountain Iron, Minnesota, at a depth of 0.0 km and coordinates 47.6128°, -92.6682°.
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
-92.6682°E
Technical Information
Common Questions
How strong was the magnitude 3.1 earthquake near Mountain Iron, Minnesota?
The magnitude 3.1 earthquake that struck 9 km NNW of Mountain Iron, Minnesota on December 8, 2020 at 18:30 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: us7000cp87). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, December 8, 2020). M3.1 Earthquake 9 km NNW of Mountain Iron, Minnesota — December 8, 2020. Retrieved February 12, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000cp87/