M4.3 Earthquake 113 km SSW of Nikolski, Alaska — April 17, 2025
2025-04-17 18:17:49 UTC (2025-04-17) · approx. 7:17 AM UTC-11 local
On April 17, 2025 at 18:17 UTC, a magnitude 4.3 shallow crustal earthquake struck 113 km SSW of Nikolski, Alaska, at a depth of 12.9 km and coordinates 51.9879°, -169.4531°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 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
-169.4531°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.3 earthquake near Nikolski, Alaska?
The magnitude 4.3 earthquake that struck 113 km SSW of Nikolski, Alaska on April 17, 2025 at 18:17 UTC had a depth of 12.9 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 4.3 earthquakes can continue for several days and gradually diminish over time.
Actions
Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000q6uf). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, April 17, 2025). M4.3 Earthquake 113 km SSW of Nikolski, Alaska — April 17, 2025. Retrieved June 27, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000q6uf/