M3.8 Earthquake 234 km ESE of Attu Station, Alaska — April 6, 2026
2026-04-06 23:34:38 UTC (2026-04-06) · approx. 11:34 AM UTC+12 local
On April 6, 2026 at 23:34 UTC, a magnitude 3.8 shallow crustal earthquake struck 234 km ESE of Attu Station, Alaska, at a depth of 10.0 km and coordinates 51.8151°, 176.1906°.
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.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.0 mainshock that occurred 1 day ago near Rat Islands, Aleutian Islands, Alaska. Since the mainshock, the USGS has recorded 46 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
176.1906°E
Technical Information
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Common Questions
How strong was the magnitude 3.8 earthquake near Attu Station, Alaska?
The magnitude 3.8 earthquake that struck 234 km ESE of Attu Station, Alaska on April 6, 2026 at 23:34 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.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 3.8 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier near Rat Islands, Aleutian Islands, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 3.8 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us7000sb5f). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, April 6, 2026). M3.8 Earthquake 234 km ESE of Attu Station, Alaska — April 6, 2026. Retrieved June 20, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000sb5f/