1960 Valdivia earthquake
The 1960 Valdivia earthquake () or Great Chilean earthquake ("Gran terremoto de Chile") of 22 May is the most powerful earthquake ever recorded. Various studies have placed it at 9.4–9.6 on the moment magnitude scale. It occurred in the afternoon (19:11 GMT, 15:11 local time), and lasted approximately 10 minutes. The resulting tsunami affected southern Chile, Hawaii, Japan, the Philippines, eastern New Zealand, southeast Australia and the Aleutian Islands.
1964 Alaska earthquake
Lasting four minutes and thirty-eight seconds, the magnitude 9.2 megathrust earthquake remains the most powerful earthquake recorded in North American history, and the second most powerful earthquake recorded in world history. of fault ruptured at once and moved up to , releasing about 500 years of stress buildup. Soil liquefaction, fissures, landslides, and other ground failures caused major structural damage in several communities and much damage to property. Anchorage sustained great destruction or damage to many inadequately earthquake-engineered houses, buildings, and infrastructure (paved streets, sidewalks, water and sewer mains, electrical systems, and other man-made equipment), particularly in the several landslide zones along Knik Arm. southwest, some areas near Kodiak were permanently raised by . Southeast of Anchorage, areas around the head of Turnagain Arm near Girdwood and Portage dropped as much as , requiring reconstruction and fill to raise the Seward Highway above the new high tide mark.