M4.1 Earthquake 70 km SW of Nikolski, Alaska — September 16, 2023
2023-09-16 23:59:21 UTC (2023-09-16) · approx. 12:59 PM UTC-11 local
On September 16, 2023 at 23:59 UTC, a magnitude 4.1 shallow crustal earthquake struck 70 km SW of Nikolski, Alaska, at a depth of 35.0 km and coordinates 52.4305°, -169.4823°.
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.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Earthquake Details
-169.4823°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.1 earthquake near Nikolski, Alaska?
The magnitude 4.1 earthquake that struck 70 km SW of Nikolski, Alaska on September 16, 2023 at 23:59 UTC had a depth of 35.0 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: us7000kwa9). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, September 16, 2023). M4.1 Earthquake 70 km SW of Nikolski, Alaska — September 16, 2023. Retrieved November 18, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000kwa9/