Not all earthquakes produce tsunamis, but when they do, the waves may sweep ashore causing damage locally and at places thousands of miles from the earthquake epicenter. More than 90 percent of the deaths from the 1964 earthquake were a result of tsunamis. One hundred six Alaskans died from these waves and an additional 16 people died from tsunamis in California and Oregon. There are several ways tsunamis are produced. Tsunamis started this way can travel long distances and cause destruction thousands of miles from where the wave was generated.
Underwater landslides are another cause of tsunamis.
Destruction in Seward, Whittier, and Valdez, and other places in 1964 was from these underwater landslides. These tsunamis are localized. Above water landslides can also cause local tsunamis if they enter a body of water. The wave ran up a mountainside on the opposite side of the bay to a height of more than 1,720 feet. Two fishing vessels anchored in the bay were sunk and two people died.