August 11, 2024 18:58:12 AKDT (August 12, 2024 02:58:12 UTC)
60.5033°N 145.1878°W Depth 10.2 miles (16 km)
This event has not been verified by a seismologist
- 50 miles (81 km) south of Thompson Pass
- 56 miles (90 km) southeast of Tatitlek
- 58 miles (94 km) southeast of Valdez
- 67 miles (108 km) south of Pumping Station No. 12
- 74 miles (119 km) south of Chitina
- 82 miles (132 km) northeast of Middleton Island
- 99 miles (160 km) west of Cape Yakataga
- 100 miles (162 km) east of Chenega Bay
- 100 miles (162 km) south of Copper Center
- 100 miles (162 km) southwest of McCarthy
- 110 miles (178 km) south of Pumping Station No. 11
- 166 miles (269 km) east of Anchorage
- 200 miles (324 km) west of Yakutat
- 310 miles (502 km) south of Fairbanks
- 408 miles (661 km) northwest of Juneau
- Size Type: Mm2
- Event type: Earthquake
Tectonic position of southern Alaska
Earthquakes in southcentral Alaska are caused by a number of different tectonic features. (1) The largest earthquakes in southcentral Alaska are caused by the megathrust fault that marks the contact zone between the subducting Pacific Plate and the overlying North American Plate. The 1964 Great Alaska earthquake of magnitude 9.2, which remains the second largest earthquake ever recorded worldwide, originated beneath Prince William Sound. (2) Intermediate depth seismicity (less than 20 miles/32 km) occurs in the Wadati-Benioff Zone, where the subducting Pacific Plate descends toward the mantle beneath the North American Plate. This zone extends along the Aleutian Arc, the Alaska Peninsula, and Cook Inlet, and ends beneath the northern reaches of the Alaska Range. In southern and central Alaska, this seismicity subsides at a depth of about 140 miles (225 km), reflecting the downward extension of the Pacific Plate. The magnitude 7.1 Iniskin quake in 2016 and the magnitude 7.1 Anchorage quake in 2018 are the most recent notable intermediate-depth events. Both caused significant ground shaking in the Southcentral region and resulted in structural damage to buildings and infrastructure. (3) Crustal seismicity in this region can be attributed to three main sources: the faults and folds of the Cook Inlet Basin, the Castle Mountain Fault, and the broad band of diffuse seismicity extending from northern Cook Inlet to the Denali Fault. Mapped geologic structures in the upper Cook Inlet can trigger strong earthquakes. The magnitude 6.9 earthquake of April 1933 that caused significant damage in Anchorage appears to have occurred on such a structure. The Castle Mountain Fault, which runs 40 kilometers north of Anchorage, shows geological evidence of Holocene slip and triggered the magnitude 5.6 Sutton earthquake of 1984. The diffuse seismic zone between Cook Inlet and the Denali Fault may mark a deformation zone between the Bering microplate to the west and the southern Alaska block to the east. This broad seismic zone includes a series of predominantly thrust faults, and a magnitude 7.0 earthquake in 1943 may have originated in this band.