M3.9 Earthquake 42 km WNW of Nikolski, Alaska — August 10, 2021
2021-08-10 22:52:47 UTC (2021-08-10) · approx. 11:52 AM UTC-11 local
On August 10, 2021 at 22:52 UTC, a magnitude 3.9 intermediate depth earthquake struck 42 km WNW of Nikolski, Alaska, at a depth of 135.8 km and coordinates 53.0261°, -169.4729°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-169.4729°E
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Common Questions
How strong was the magnitude 3.9 earthquake near Nikolski, Alaska?
The magnitude 3.9 earthquake that struck 42 km WNW of Nikolski, Alaska on August 10, 2021 at 22:52 UTC had a depth of 135.8 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 3.9 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000f8e3). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, August 10, 2021). M3.9 Earthquake 42 km WNW of Nikolski, Alaska — August 10, 2021. Retrieved October 23, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000f8e3/