A landslide can occur when rocks and debris form an avalanche, often after an earthquake. A cut-slope slip refers to a small landslide in a road cut,
Mudslide consists of an admixture of soil and water which may contain rocks, trees and other debris.
A debris flow is like a mudslide but contains other materials, such as volcanic ash or slag. Lahar is an Indonesian term for a combined volcanic ash, rock debris and mudslide associated with a volcano or volcanic fallout.
Risk factors:
(1) steeply sloped surface, especially the site of a previous landslide or if there is evidence of erosion
(2) no or reduced retention of material (deforestation, development, wildfire)
(3) increased movable material (slag mountain, volcanic ash)
(4) large amount of water that oversaturates the soil(heavy rains, rapidly melting snows, flooding)
(5) earthquake or volcanic eruption
(6) base of any water runoff - drainage channel, stream bed, ravine or gully
