M3.1 Earthquake 252 km SSE of Attu Station, Alaska — July 24, 2021
2021-07-24 21:33:56 UTC (2021-07-24) · approx. 9:33 AM UTC+12 local
On July 24, 2021 at 21:33 UTC, a magnitude 3.1 shallow crustal earthquake struck 252 km SSE of Attu Station, Alaska, at a depth of 11.6 km and coordinates 50.8199°, 174.8417°.
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
174.8417°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near Attu Station, Alaska?
The magnitude 3.1 earthquake that struck 252 km SSE of Attu Station, Alaska on July 24, 2021 at 21:33 UTC had a depth of 11.6 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 3.1 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: ak0219fdvfy9). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 24, 2021). M3.1 Earthquake 252 km SSE of Attu Station, Alaska — July 24, 2021. Retrieved October 21, 2021 from https://www.earthquaketracker.org/earthquakes/event/ak0219fdvfy9/