M4.1 Earthquake 110 km SSE of Sand Point, Alaska — October 21, 2020
2020-10-21 23:22:22 UTC (2020-10-21) · approx. 12:22 PM UTC-11 local
On October 21, 2020 at 23:22 UTC, a magnitude 4.1 shallow crustal earthquake struck 110 km SSE of Sand Point, Alaska, at a depth of 23.0 km and coordinates 54.4384°, -159.7567°.
Physical scale: An earthquake of magnitude 4.1 releases seismic energy equivalent to roughly 21 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 406 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-159.7567°E
Technical Information
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Common Questions
How strong was the magnitude 4.1 earthquake near Sand Point, Alaska?
The magnitude 4.1 earthquake that struck 110 km SSE of Sand Point, Alaska on October 21, 2020 at 23:22 UTC had a depth of 23.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.1 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.1 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000cb2h). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, October 21, 2020). M4.1 Earthquake 110 km SSE of Sand Point, Alaska — October 21, 2020. Retrieved January 9, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000cb2h/