The magnitude 9.2 earthquake that struck Alaska on March 27, 1964 was the second-largest earthquake recorded in modern times (after a 9.5 earthquake in Chile in 1960), and the largest in the written history of North America. It released 100 times as much energy as the 1906 San Francisco earthquake and was followed by tsunamis. During the earthquake, more than 100,000 square miles of Alaska broke, twisted, tilted, dropped and rose.