M4.0 Earthquake 250 km ESE of Chiniak, Alaska — July 16, 2021
2021-07-16 20:01:34 UTC (2021-07-16) · approx. 10:01 AM UTC-10 local
On July 16, 2021 at 20:01 UTC, a magnitude 4.0 shallow crustal earthquake struck 250 km ESE of Chiniak, Alaska, at a depth of 17.2 km and coordinates 56.4981°, -148.6894°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-148.6894°E
Technical Information
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Common Questions
How strong was the magnitude 4.0 earthquake near Chiniak, Alaska?
The magnitude 4.0 earthquake that struck 250 km ESE of Chiniak, Alaska on July 16, 2021 at 20:01 UTC had a depth of 17.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.0 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000emnt). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 16, 2021). M4.0 Earthquake 250 km ESE of Chiniak, Alaska — July 16, 2021. Retrieved November 4, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000emnt/