The sliding of a large mass of rock material or soil down the side of a mountain or cliff. All landslides have two things in common – they are the result of failure of the soil and rock materials that make up the hill slope and they are driven by gravity.
Landslides can be triggered by natural causes such as earthquake vibrations, undercutting of cliffs and banks by waves or river erosion, and volcanic eruptions. They can also be the result of human activity such as mining activities, depletion of vegetation and the modification of slopes for construction. Landslides range from a single boulder in a rock fall to tens of millions of cubic metres of material in a debris flow.
Image: Landslide in Morocco, Kariido85 (Flickr), 31 July 2010