The 1964 Alaska earthquake had a magnitude of 9.2. Also called the Great Alaska earthquake or Good Friday earthquake, it remains the most powerful earthquake ever recorded in North America.
The megathrust earthquake struck on March 27, 1964, in Prince William Sound, south-central Alaska. The rupture occurred where the Pacific Plate is forced beneath the North American Plate and extended for roughly 600 miles. Shaking lasted about four minutes and thirty-eight seconds, causing landslides, soil liquefaction, fissures, and major damage in Anchorage and other communities.
The earthquake displaced parts of Alaska dramatically. Some areas were uplifted by more than 30 feet, while others subsided several feet. The seafloor movement generated a major tsunami, and additional waves were triggered by underwater and coastal landslides. In total, about 139 people died.
A frequent source of confusion is the magnitude range reported in different references: some list 9.2, while others give 9.2–9.3. The quiz's 9.2 is the standard value used by the U.S. Geological Survey and is the canonical answer.