M4.3 Earthquake 289 km W of Adak, Alaska — July 31, 2023
2023-07-31 14:56:37 UTC (2023-07-31) · approx. 2:56 AM UTC+12 local
On July 31, 2023 at 14:56 UTC, a magnitude 4.3 intermediate depth earthquake struck 289 km W of Adak, Alaska, at a depth of 192.9 km and coordinates 52.3402°, 179.2084°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 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
179.2084°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.3 earthquake near Adak, Alaska?
The magnitude 4.3 earthquake that struck 289 km W of Adak, Alaska on July 31, 2023 at 14:56 UTC had a depth of 192.9 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 4.3 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000kwuz). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, July 31, 2023). M4.3 Earthquake 289 km W of Adak, Alaska — July 31, 2023. Retrieved October 7, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kwuz/