M3.6 Earthquake 47 km WSW of Nikolski, Alaska — September 18, 2026
2026-09-18 16:56:17 UTC (1 day ago) · approx. 5:56 AM UTC-11 local
On September 18, 2026 at 16:56 UTC, a magnitude 3.6 intermediate depth earthquake struck 47 km WSW of Nikolski, Alaska, at a depth of 70.3 km and coordinates 52.7823°, -169.5249°.
Physical scale: An earthquake of magnitude 3.6 releases seismic energy equivalent to roughly 3.8 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 184 m — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.0 mainshock that occurred 15 days ago 63 km SSW of Nikolski, Alaska. Since the mainshock, the USGS has recorded 24 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
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
-169.5249°E
Technical Information
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Common Questions
How strong was the magnitude 3.6 earthquake near Nikolski, Alaska?
The magnitude 3.6 earthquake that struck 47 km WSW of Nikolski, Alaska on September 18, 2026 at 16:56 UTC had a depth of 70.3 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 3.6 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 3.6 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 63 km SSW of Nikolski, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 3.6 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us7000tiet). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, September 18, 2026). M3.6 Earthquake 47 km WSW of Nikolski, Alaska — September 18, 2026. Retrieved September 19, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000tiet/