M3.7 Earthquake 53 km WSW of Attu Station, Alaska — October 30, 2021
2021-10-30 21:36:18 UTC (2021-10-30) · approx. 8:36 AM UTC+11 local
On October 30, 2021 at 21:36 UTC, a magnitude 3.7 shallow crustal earthquake struck 53 km WSW of Attu Station, Alaska, at a depth of 41.6 km and coordinates 52.6344°, 172.4787°.
Physical scale: An earthquake of magnitude 3.7 releases seismic energy equivalent to roughly 5.4 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 215 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
172.4787°E
Technical Information
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Common Questions
How strong was the magnitude 3.7 earthquake near Attu Station, Alaska?
The magnitude 3.7 earthquake that struck 53 km WSW of Attu Station, Alaska on October 30, 2021 at 21:36 UTC had a depth of 41.6 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 3.7 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.7 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us7000frfj). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 30, 2021). M3.7 Earthquake 53 km WSW of Attu Station, Alaska — October 30, 2021. Retrieved January 14, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000frfj/