M4.0 Earthquake 229 km W of Adak, Alaska — August 16, 2023
2023-08-16 22:19:35 UTC (2023-08-16) · approx. 10:19 AM UTC-12 local
On August 16, 2023 at 22:19 UTC, a magnitude 4.0 intermediate depth earthquake struck 229 km W of Adak, Alaska, at a depth of 222.6 km and coordinates 52.1068°, -179.9487°.
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
-179.9487°E
Technical Information
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Common Questions
How strong was the magnitude 4.0 earthquake near Adak, Alaska?
The magnitude 4.0 earthquake that struck 229 km W of Adak, Alaska on August 16, 2023 at 22:19 UTC had a depth of 222.6 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: us7000knwc). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, August 16, 2023). M4.0 Earthquake 229 km W of Adak, Alaska — August 16, 2023. Retrieved October 27, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000knwc/