M3.3 Earthquake 109 km SSW of Port Alexander, Alaska — September 23, 2023
2023-09-23 21:52:39 UTC (2023-09-23) · approx. 12:52 PM UTC-9 local
On September 23, 2023 at 21:52 UTC, a magnitude 3.3 shallow crustal earthquake struck 109 km SSW of Port Alexander, Alaska, at a depth of 4.5 km and coordinates 55.3753°, -135.4307°.
Physical scale: An earthquake of magnitude 3.3 releases seismic energy equivalent to roughly 1.3 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 114 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 2 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-135.4307°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.3 earthquake near Port Alexander, Alaska?
The magnitude 3.3 earthquake that struck 109 km SSW of Port Alexander, Alaska on September 23, 2023 at 21:52 UTC had a depth of 4.5 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 3.3 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.3 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: ak023c89rne3). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, September 23, 2023). M3.3 Earthquake 109 km SSW of Port Alexander, Alaska — September 23, 2023. Retrieved December 2, 2023 from https://www.earthquaketracker.org/earthquakes/event/ak023c89rne3/