M3.8 Earthquake 103 km S of Adak, Alaska — September 28, 2025
2025-09-28 20:31:13 UTC (2025-09-28) · approx. 8:31 AM UTC-12 local
On September 28, 2025 at 20:31 UTC, a magnitude 3.8 shallow crustal earthquake struck 103 km S of Adak, Alaska, at a depth of 10.0 km and coordinates 50.9591°, -176.9036°.
Physical scale: An earthquake of magnitude 3.8 releases seismic energy equivalent to roughly 7.6 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 252 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-176.9036°E
Technical Information
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Common Questions
How strong was the magnitude 3.8 earthquake near Adak, Alaska?
The magnitude 3.8 earthquake that struck 103 km S of Adak, Alaska on September 28, 2025 at 20:31 UTC had a depth of 10.0 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 3.8 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.8 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000rdhj). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 28, 2025). M3.8 Earthquake 103 km S of Adak, Alaska — September 28, 2025. Retrieved December 11, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000rdhj/