Fifty years ago, on March 27, 1964 at 5:36pm local time, a huge, magnitude 9.2 earthquake rattled the state of Alaska. The quake's epicenter was located about 75 miles east of Anchorage, at a depth of 15 miles. Violent shaking lasted about 4 minutes and triggered several avalanches and landslides, and caused damage to many of Alaska's major cities including Anchorage. Quake-generated tsunamis caused additional damage. A 30-ft wave destroyed Kodiak, Alaska's ocean-front industries and much of the city's fishing fleet.

Despite it being the 2nd largest earthquake ever recorded (a 1960 Chinese quake measured magnitude 9.5), Alaska's Good Friday quake and resulting tsunami caused only 131 deaths (115 in Alaska; 16 in Oregon and California!).

As noted in the video at the top of the page, the Alaska earthquake took place just as plate tectonics was gaining acceptance in the scientific community. The idea of moving and colliding crustal plates had been around since the early 1920s but didn't gain any serious foothold until the 1960s. The developing theory helped explain the 1964 Great Alaska Earthquake, which was the result of subduction of the Pacific plate beneath the North American plate.

More scientific information can be found here and here.

The video below show some of the quake's effects in Anchorage and elsewhere.