M3.5 Earthquake 199 km WSW of Adak, Alaska — July 20, 2026
2026-07-20 15:47:11 UTC (16 hours ago) · approx. 3:47 AM UTC-12 local
On July 20, 2026 at 15:47 UTC, a magnitude 3.5 shallow crustal earthquake struck 199 km WSW of Adak, Alaska, at a depth of 8.7 km and coordinates 51.0070°, -179.1410°.
Physical scale: An earthquake of magnitude 3.5 releases seismic energy equivalent to roughly 2.7 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 157 m — a useful intuition for the size of the slip patch on the fault.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Earthquake Details
-179.1410°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.5 earthquake near Adak, Alaska?
The magnitude 3.5 earthquake that struck 199 km WSW of Adak, Alaska on July 20, 2026 at 15:47 UTC had a depth of 8.7 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 3.5 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.5 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: aka2026ogpyyr). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, July 20, 2026). M3.5 Earthquake 199 km WSW of Adak, Alaska — July 20, 2026. Retrieved July 20, 2026 from https://www.earthquaketracker.org/earthquakes/event/aka2026ogpyyr/