M3.3 Earthquake 50 km E of Juneau, Alaska — September 28, 2021
2021-09-28 17:12:53 UTC (2021-09-28) · approx. 8:12 AM UTC-9 local
On September 28, 2021 at 17:12 UTC, a magnitude 3.3 shallow crustal earthquake struck 50 km E of Juneau, Alaska, at a depth of 5.0 km and coordinates 58.3006°, -133.5575°.
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.
Earthquake Details
-133.5575°E
Technical Information
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Common Questions
How strong was the magnitude 3.3 earthquake near Juneau, Alaska?
The magnitude 3.3 earthquake that struck 50 km E of Juneau, Alaska on September 28, 2021 at 17:12 UTC had a depth of 5.0 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 3.3 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: us6000fpun). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, September 28, 2021). M3.3 Earthquake 50 km E of Juneau, Alaska — September 28, 2021. Retrieved December 4, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000fpun/