M3.1 Earthquake 136 km E of McCarthy, Alaska — July 17, 2021
2021-07-17 21:47:05 UTC (2021-07-17) · approx. 12:47 PM UTC-9 local
On July 17, 2021 at 21:47 UTC, a magnitude 3.1 shallow crustal earthquake struck 136 km E of McCarthy, Alaska, at a depth of 3.1 km and coordinates 61.4620°, -140.3653°.
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
-140.3653°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near McCarthy, Alaska?
The magnitude 3.1 earthquake that struck 136 km E of McCarthy, Alaska on July 17, 2021 at 21:47 UTC had a depth of 3.1 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: us7000en0c). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 17, 2021). M3.1 Earthquake 136 km E of McCarthy, Alaska — July 17, 2021. Retrieved November 4, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000en0c/