M3.9 Earthquake 107 km SSE of Adak, Alaska — October 17, 2026
2026-10-17 03:33:59 UTC (1 hour ago) · approx. 3:33 PM UTC-12 local
On October 17, 2026 at 03:33 UTC, a magnitude 3.9 shallow crustal earthquake struck 107 km SSE of Adak, Alaska, at a depth of 11.0 km and coordinates 50.9517°, -176.1727°.
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.
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
-176.1727°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.9 earthquake near Adak, Alaska?
The magnitude 3.9 earthquake that struck 107 km SSE of Adak, Alaska on October 17, 2026 at 03:33 UTC had a depth of 11.0 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 3.9 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: us6000u2xm). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, October 17, 2026). M3.9 Earthquake 107 km SSE of Adak, Alaska — October 17, 2026. Retrieved October 17, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000u2xm/