M4.2 Earthquake 63 km WSW of Adak, Alaska — February 4, 2023
2023-02-04 18:09:48 UTC (2023-02-04) · approx. 6:09 AM UTC-12 local
On February 4, 2023 at 18:09 UTC, a magnitude 4.2 intermediate depth earthquake struck 63 km WSW of Adak, Alaska, at a depth of 71.5 km and coordinates 51.7352°, -177.5302°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 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
-177.5302°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near Adak, Alaska?
The magnitude 4.2 earthquake that struck 63 km WSW of Adak, Alaska on February 4, 2023 at 18:09 UTC had a depth of 71.5 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 4.2 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000jlfm). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, February 4, 2023). M4.2 Earthquake 63 km WSW of Adak, Alaska — February 4, 2023. Retrieved April 13, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000jlfm/