M3.5 Earthquake 129 km S of Unalaska, Alaska — January 21, 2025
2025-01-21 19:30:40 UTC (2025-01-21) · approx. 8:30 AM UTC-11 local
On January 21, 2025 at 19:30 UTC, a magnitude 3.5 shallow crustal earthquake struck 129 km S of Unalaska, Alaska, at a depth of 31.7 km and coordinates 52.7107°, -166.7058°.
Physical scale: An earthquake of magnitude 3.5 releases seismic energy equivalent to roughly 2.7 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 157 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-166.7058°E
Technical Information
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Common Questions
How strong was the magnitude 3.5 earthquake near Unalaska, Alaska?
The magnitude 3.5 earthquake that struck 129 km S of Unalaska, Alaska on January 21, 2025 at 19:30 UTC had a depth of 31.7 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 3.5 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.5 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us7000pee3). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, January 21, 2025). M3.5 Earthquake 129 km S of Unalaska, Alaska — January 21, 2025. Retrieved March 29, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000pee3/