M3.1 Earthquake 246 km W of Adak, Alaska — October 31, 2021
2021-10-31 21:45:32 UTC (2021-10-31) · approx. 9:45 AM UTC+12 local
On October 31, 2021 at 21:45 UTC, a magnitude 3.1 intermediate depth earthquake struck 246 km W of Adak, Alaska, at a depth of 164.1 km and coordinates 51.8989°, 179.7914°.
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
179.7914°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near Adak, Alaska?
The magnitude 3.1 earthquake that struck 246 km W of Adak, Alaska on October 31, 2021 at 21:45 UTC had a depth of 164.1 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: us7000fus9). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 31, 2021). M3.1 Earthquake 246 km W of Adak, Alaska — October 31, 2021. Retrieved January 14, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000fus9/