The content describes a seismic event that occurred in Southern Alaska on December 9, 2023. The earthquake had a magnitude of Ml2 and occurred at a depth of 26.8 miles. It was located 16 miles northeast of Soldotna and 19 miles northeast of Kenai. The tectonic setting of Southern Alaska is also discussed, with earthquakes being produced by various tectonic features such as the megathrust fault, the Wadati-Benioff Zone, and crustal seismicity from the faults and folds of the Cook Inlet basin.
The strongest earthquakes in the region are generated by the megathrust fault, while intermediate-depth seismicity occurs in the Wadati-Benioff Zone. Crustal seismicity is attributed to the faults and folds of the Cook Inlet basin, the Castle Mountain Fault, and a wide band of diffuse seismicity extending from northern Cook Inlet to the Denali Fault. This seismic event is placed in the context of historical earthquakes in the region, such as the 1964 Great Alaska Earthquake and the 2016 M7.1 Iniskin and the 2018 M7.1 Anchorage earthquakes.
The Castle Mountain Fault and the diffuse zone of seismicity are specifically highlighted as potential sources of strong earthquakes and the 1933 M6.9 earthquake, as well as the 1984 M5.6 Sutton Earthquake, are mentioned as examples.