M3.9 Earthquake 112 km ENE of Atka, Alaska — March 15, 2021
2021-03-15 20:04:44 UTC (2021-03-15) · approx. 8:04 AM UTC-12 local
On March 15, 2021 at 20:04 UTC, a magnitude 3.9 intermediate depth earthquake struck 112 km ENE of Atka, Alaska, at a depth of 211.3 km and coordinates 52.7294°, -172.7994°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-172.7994°E
Technical Information
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Common Questions
How strong was the magnitude 3.9 earthquake near Atka, Alaska?
The magnitude 3.9 earthquake that struck 112 km ENE of Atka, Alaska on March 15, 2021 at 20:04 UTC had a depth of 211.3 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 3.9 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000dza5). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, March 15, 2021). M3.9 Earthquake 112 km ENE of Atka, Alaska — March 15, 2021. Retrieved May 26, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000dza5/