M3.1 Earthquake 99 km SSE of Sand Point, Alaska — November 23, 2021
2021-11-23 19:31:39 UTC (2021-11-23) · approx. 8:31 AM UTC-11 local
On November 23, 2021 at 19:31 UTC, a magnitude 3.1 shallow crustal earthquake struck 99 km SSE of Sand Point, Alaska, at a depth of 26.5 km and coordinates 54.5551°, -159.7340°.
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
-159.7340°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near Sand Point, Alaska?
The magnitude 3.1 earthquake that struck 99 km SSE of Sand Point, Alaska on November 23, 2021 at 19:31 UTC had a depth of 26.5 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: us6000gfs8). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, November 23, 2021). M3.1 Earthquake 99 km SSE of Sand Point, Alaska — November 23, 2021. Retrieved January 29, 2022 from https://www.earthquaketracker.org/earthquakes/event/us6000gfs8/