The 1963 Vaiont landslide, Italy

The Vaiont landslide in northern Italy is one of the best-known and most tragic natural disasters induced by human activity. On 9 October 1963, about 270 million m3 of rock slid into the newly created Vaiont reservoir. The slide moved a 250-m-thick mass of rock 300- 400 m horizontally with an estimated velocity of 20-30 m s-1, before running up and stopping against the opposite side of the Vaiont valley. Most of the slide mass moved as a block and reached the opposite side of the valley with little change in shape apart from a rotation that is evident from both the surface morphology and the stratigraphic sequence. The landslide generated a displacement wave that overtopped the arched Vaiont Dam and flooded settlements below, killing over 2000 people. The dam resisted the forces imposed by the landslide and suffered only minor damage. The Vaiont landslide helped lay the foundation for modern engineering geology by establishing a new vision for evaluating landslide hazard and applying rock mechanics to slope stability.