The earthquake that occurred on February 16, 2024 at 22:18:02 AKST (February 17, 2024 at 07:18:02 UTC) had a magnitude of 2. The location of the earthquake was 61.6412°N, 149.7955°W, with a depth of 16.6 miles (26 km). It was situated 13 miles (21 km) west of Wasilla, 18 miles (29 km) southwest of Hatcher Pass, 20 miles (32 km) northwest of Chugiak, 23 miles (37 km) north of Eagle River, and 23 miles (37 km) west of Palmer. Additionally, it was located 27 miles (43 km) north of Elmendorf AFB, 27 miles (43 km) north of Fort Richardson, 29 miles (47 km) north of Anchorage, 30 miles (48 km) west of Sutton, 48 miles (77 km) south of Talkeetna, 50 miles (81 km) north of Hope, 230 miles (372 km) south of Fairbanks, and 281 miles (455 km) north of Kodiak.
The tectonic setting of southern Alaska plays a significant role in seismic activity. Earthquakes in Southcentral Alaska are the result of various tectonic factors. The megathrust fault, which marks the junction between the subducting Pacific and overriding North American plates, is responsible for the most powerful earthquakes in the region. The 1964 M9.2 Great Alaska Earthquake, the second largest earthquake ever recorded globally, originated under Prince William Sound. Additionally, intermediate-depth seismic activity occurs in the Wadati-Benioff Zone, where the subducting Pacific Plate descends towards the mantle beneath the North American Plate. This zone extends along the Aleutian Arc, Alaska Peninsula, and Cook Inlet and terminates beneath the northern foothills of the Alaska Range. Furthermore, crustal seismic activity is attributed to the faults and folds of the Cook Inlet basin, the Castle Mountain Fault, and a broad band of diffuse seismicity extending from northern Cook Inlet to the Denali Fault.
The 2016 M7.1 Iniskin and the 2018 M7.1 Anchorage earthquakes are the most recent notable intermediate-depth events. Both earthquakes resulted in significant ground shaking in the Southcentral region and caused structural damage to buildings and infrastructure. Additionally, the geological structures in upper Cook Inlet are capable of generating strong earthquakes. For example, the April 1933 M6.9 earthquake caused considerable damage in Anchorage and may have occurred on such a structure.
The Castle Mountain Fault, which passes 25 miles (40 km) north of Anchorage, has geological evidence of Holocene offsets and generated the 1984 M5.6 Sutton Earthquake. The diffuse zone of seismicity between Cook Inlet and the Denali Fault may indicate a deformation zone between the Bering microplate and the southern Alaska block, including a series of predominantly thrust faults, and a 1943 M7.0 earthquake may have originated in this zone.
Understanding the tectonic setting of southern Alaska can provide valuable insights into the nature and characteristics of earthquakes in the region. As editorial director, we aim to provide informative content about seismic events and their underlying geological factors for our readers to stay informed and prepared.
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