M4.0 Earthquake 111 km SE of False Pass, Alaska — October 2, 2021
2021-10-02 19:50:28 UTC (2021-10-02) · approx. 8:50 AM UTC-11 local
On October 2, 2021 at 19:50 UTC, a magnitude 4.0 shallow crustal earthquake struck 111 km SE of False Pass, Alaska, at a depth of 47.4 km and coordinates 54.0398°, -162.4178°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-162.4178°E
Technical Information
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Common Questions
How strong was the magnitude 4.0 earthquake near False Pass, Alaska?
The magnitude 4.0 earthquake that struck 111 km SE of False Pass, Alaska on October 2, 2021 at 19:50 UTC had a depth of 47.4 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.0 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000fsmm). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 2, 2021). M4.0 Earthquake 111 km SE of False Pass, Alaska — October 2, 2021. Retrieved December 10, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000fsmm/