M4.0 Earthquake 92 km SSW of Unalaska, Alaska — September 15, 2026
2026-09-15 05:21:25 UTC (10 hours ago) · approx. 6:21 PM UTC-11 local
On September 15, 2026 at 05:21 UTC, a magnitude 4.0 shallow crustal earthquake struck 92 km SSW of Unalaska, Alaska, at a depth of 18.4 km and coordinates 53.0990°, -167.0280°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 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
-167.0280°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.0 earthquake near Unalaska, Alaska?
The magnitude 4.0 earthquake that struck 92 km SSW of Unalaska, Alaska on September 15, 2026 at 05:21 UTC had a depth of 18.4 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 4.0 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: aka2026shcitc). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, September 15, 2026). M4.0 Earthquake 92 km SSW of Unalaska, Alaska — September 15, 2026. Retrieved September 15, 2026 from https://www.earthquaketracker.org/earthquakes/event/aka2026shcitc/