The Good Friday earthquake of 1964 brought unexpected destruction to the city of Anchorage, Alaska. In the Anchorage area, the quake registered 8.5 on the Richter scale. Though the seismic vibrations were ruinous, the major cause of damage to the city was slab slides. These slides were related to the quick clay properties of Bootlegger Cove Clay which underlies most of Anchorage. Prolonged seismic activity triggered huge masses of earth, initially bounded on one side by a bluff, to move laterally upon a horizontal and planar shear surface within the clay. The lateral displacement of many slides was extensive, and one major slide transported earth more than half a mile. Grabens formed as a result of faulting and collapsing of the sediments within the slab slide. Although the Bootlegger Cove Clay bed is shallow, its presence greatly augmented the destructiveness of the earthquake.