M3.4 Earthquake 215 km SE of Chignik, Alaska — September 12, 2025
2025-09-12 20:20:50 UTC (2025-09-12) · approx. 10:20 AM UTC-10 local
On September 12, 2025 at 20:20 UTC, a magnitude 3.4 shallow crustal earthquake struck 215 km SE of Chignik, Alaska, at a depth of 57.2 km and coordinates 54.8519°, -156.1369°.
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
-156.1369°E
Technical Information
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Common Questions
How strong was the magnitude 3.4 earthquake near Chignik, Alaska?
The magnitude 3.4 earthquake that struck 215 km SE of Chignik, Alaska on September 12, 2025 at 20:20 UTC had a depth of 57.2 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: ak025bq22k90). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 12, 2025). M3.4 Earthquake 215 km SE of Chignik, Alaska — September 12, 2025. Retrieved December 3, 2025 from https://www.earthquaketracker.org/earthquakes/event/ak025bq22k90/