M3.1 Earthquake 138 km S of Akhiok, Alaska — July 30, 2021
2021-07-30 22:04:01 UTC (2021-07-30) · approx. 12:04 PM UTC-10 local
On July 30, 2021 at 22:04 UTC, a magnitude 3.1 shallow crustal earthquake struck 138 km S of Akhiok, Alaska, at a depth of 10.0 km and coordinates 55.7152°, -154.4764°.
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
-154.4764°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near Akhiok, Alaska?
The magnitude 3.1 earthquake that struck 138 km S of Akhiok, Alaska on July 30, 2021 at 22:04 UTC had a depth of 10.0 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: us6000f2qu). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 30, 2021). M3.1 Earthquake 138 km S of Akhiok, Alaska — July 30, 2021. Retrieved October 14, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000f2qu/