M3.4 Earthquake 90 km SSW of Unalaska, Alaska — August 12, 2025
2025-08-12 23:22:05 UTC (2025-08-12) · approx. 12:22 PM UTC-11 local
On August 12, 2025 at 23:22 UTC, a magnitude 3.4 shallow crustal earthquake struck 90 km SSW of Unalaska, Alaska, at a depth of 35.0 km and coordinates 53.0864°, -166.8862°.
Physical scale: An earthquake of magnitude 3.4 releases seismic energy equivalent to roughly 1.9 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 134 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-166.8862°E
Technical Information
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Common Questions
How strong was the magnitude 3.4 earthquake near Unalaska, Alaska?
The magnitude 3.4 earthquake that struck 90 km SSW of Unalaska, Alaska on August 12, 2025 at 23:22 UTC had a depth of 35.0 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 3.4 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.4 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us7000qqri). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, August 12, 2025). M3.4 Earthquake 90 km SSW of Unalaska, Alaska — August 12, 2025. Retrieved October 25, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000qqri/