M3.0 Earthquake 186 km SSW of Akhiok, Alaska — July 29, 2021
2021-07-29 22:01:38 UTC (2021-07-29) · approx. 12:01 PM UTC-10 local
On July 29, 2021 at 22:01 UTC, a magnitude 3.0 shallow crustal earthquake struck 186 km SSW of Akhiok, Alaska, at a depth of 19.2 km and coordinates 55.4744°, -155.5966°.
Physical scale: An earthquake of magnitude 3.0 releases seismic energy equivalent to roughly 477 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 71 m — a useful intuition for the size of the slip patch on the fault.

Earthquake Details
-155.5966°E
Technical Information
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Common Questions
How strong was the magnitude 3.0 earthquake near Akhiok, Alaska?
The magnitude 3.0 earthquake that struck 186 km SSW of Akhiok, Alaska on July 29, 2021 at 22:01 UTC had a depth of 19.2 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 3.0 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.0 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: ak0219nnyux5). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 29, 2021). M3.0 Earthquake 186 km SSW of Akhiok, Alaska — July 29, 2021. Retrieved October 3, 2021 from https://www.earthquaketracker.org/earthquakes/event/ak0219nnyux5/