M4.4 Earthquake 39 km ESE of Nikolski, Alaska — September 23, 2021
2021-09-23 22:41:10 UTC (2021-09-23) · approx. 11:41 AM UTC-11 local
On September 23, 2021 at 22:41 UTC, a magnitude 4.4 shallow crustal earthquake struck 39 km ESE of Nikolski, Alaska, at a depth of 39.2 km and coordinates 52.7507°, -168.3645°.
Physical scale: An earthquake of magnitude 4.4 releases seismic energy equivalent to roughly 60 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 655 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-168.3645°E
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Common Questions
How strong was the magnitude 4.4 earthquake near Nikolski, Alaska?
The magnitude 4.4 earthquake that struck 39 km ESE of Nikolski, Alaska on September 23, 2021 at 22:41 UTC had a depth of 39.2 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 4.4 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.4 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000fdwu). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, September 23, 2021). M4.4 Earthquake 39 km ESE of Nikolski, Alaska — September 23, 2021. Retrieved December 3, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000fdwu/