M3.1 Earthquake 76 km SSE of Adak, Alaska — July 31, 2023
2023-07-31 20:29:35 UTC (2023-07-31) · approx. 8:29 AM UTC-12 local
On July 31, 2023 at 20:29 UTC, a magnitude 3.1 shallow crustal earthquake struck 76 km SSE of Adak, Alaska, at a depth of 20.4 km and coordinates 51.2135°, -176.3400°.
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
-176.3400°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near Adak, Alaska?
The magnitude 3.1 earthquake that struck 76 km SSE of Adak, Alaska on July 31, 2023 at 20:29 UTC had a depth of 20.4 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: us6000kz9n). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, July 31, 2023). M3.1 Earthquake 76 km SSE of Adak, Alaska — July 31, 2023. Retrieved October 7, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kz9n/