![]() This extensive zone of seismicity includes a series of predominantly thrust faults, and a M7.0 earthquake in 1943 may have originated in this band. A magnitude 5.6 earthquake struck about 22 miles south of the village of Old Harbor Monday night, about 70 miles southwest of the city of Kodiak. The diffuse zone of seismicity between Cook Inlet and the Denali Fault may mark a zone of deformation between the Bering microplate to the west and the southern Alaska block to the east. The Castle Mountain Fault, which runs 25 miles (40 km) north of Anchorage, shows geological evidence of Holocene faulting and triggered the 1984 M5.6 Sutton earthquake. It released at least twice as much energy as the San Francisco earthquake of 1906 and was felt on land over an area of almost 502,000 square miles (1,300,000 square km). The M6.9 earthquake of April 1933, which caused significant damage in Anchorage, appears to have occurred at such a structure. Alaska earthquake of 1964, earthquake that occurred in south-central Alaska on March 27, 1964, with a moment magnitude of 9.2. Mapped geological features in the upper Cook Inlet can trigger powerful earthquakes. (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 extends. Both caused significant ground shaking in the south-central region and led to structural damage to buildings and infrastructure. The 2016 M7.1 Iniskin earthquakes and the 2018 M7.1 Anchorage earthquakes are the most recent notable medium-depth events. In southern and central Alaska, this seismicity tapers off at a depth of about 140 miles (225 km), reflecting the downdip extension of the Pacific Plate. This zone extends along the Aleutian Arc, the Alaska Peninsula and Cook Inlet and ends below the northern reaches of the Alaska Range. ![]() (2) Intermediate depth seismicity (below 20 miles/32 km) occurs in the Wadati-Benioff Zone, where the subducting Pacific Plate is sinking toward the mantle beneath the North American Plate. The Great Alaska M9.2 earthquake of 1964, still the second strongest earthquake ever recorded worldwide, originated in Prince William Sound. Focal mechanism solutions indicate faulting occurred on a steeply dipping fault striking either west-southwest (left lateral) or north-northwest (right lateral). (1) The strongest earthquakes in southcentral Alaska are caused by the megathrust fault, which marks the contact zone between the subducting Pacific and overlying North American plates. The JanuM 7.9 earthquake southeast of Kodiak Island in the Gulf of Alaska occurred as the result of strike slip faulting within the shallow lithosphere of the Pacific plate. #TsunamiWarning Alaska and Canadian West Coast in Southcentral Alaska are caused by a number of different tectonic conditions. ![]() Here is the buoy which reported a 32 foot water rise shortly after the powerful 8.2 magnitude earthquake just south of Alaska. Reports said a data buoy in the affected area briefly reported a 9.7-metre water rise shortly after the earthquake hit, but other reports predicted waves of no more than 30 centimetres above tide level. People reported on social media that the quake was felt hundreds of kilometres away, in Anchorage. Radio stations in Kodiak cited conflicting witness accounts about water that was possibly receding around the island. Kodiak officials warned residents to evacuate if they lived in low-lying areas and tsunami sirens were used to notify the public.Īs many people left their homes to move inland, several schools were opened to serve as shelters. The quake was recorded about 250km southeast of Kodiak Island early on Tuesday morning.įollowing the large tremor, warnings from the National Weather Service sent to mobile phones in Alaska warned: “Emergency Alert. Tsunami watches for the US west coast were also cancelled. Keep reading list of 4 items list 1 of 4 Photos: Afghanistan hit by another earthquake in Herat region list 2 of 4 Western Afghanistan hit by third earthquake in nearly a week list 3 of 4 Afghanistan hit by second strong earthquake in days list 4 of 4 Photos: Afghans grieve as scramble for earthquake survivors continues end of list
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