M3.1 Earthquake 79 km SSE of False Pass, Alaska — October 18, 2021
2021-10-18 20:24:35 UTC (2021-10-18) · approx. 9:24 AM UTC-11 local
On October 18, 2021 at 20:24 UTC, a magnitude 3.1 shallow crustal earthquake struck 79 km SSE of False Pass, Alaska, at a depth of 35.0 km and coordinates 54.2337°, -162.8026°.
Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 674 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 83 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-162.8026°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near False Pass, Alaska?
The magnitude 3.1 earthquake that struck 79 km SSE of False Pass, Alaska on October 18, 2021 at 20:24 UTC had a depth of 35.0 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 3.1 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.1 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000g9tj). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 18, 2021). M3.1 Earthquake 79 km SSE of False Pass, Alaska — October 18, 2021. Retrieved December 25, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000g9tj/