Types of landslides

Landslides are classified by causal factors and conditions, and include falls, slides and flows. There are many attributes and criteria for identification and classification including rate of movement, type of material and nature of movement (Ramachandra et al., 2009).

Falls: Falls move through the air and land at the base of a slope. Material is detached from a steep slope or cliff and descends through the air by free fall or by bouncing or rolling down slope. Rock fall, the most common type, is a fall of detached rock from an area of in tact bedrock.

Slide: Slides move in contact with the underlying surface. They include rockslides -  the down slope movement of a rock mass along a plane surface; and slumps - the sliding of material along a curved (rotational slide) or flat (translational slide) surface. Slow moving landslides can occur on relatively gentle slopes, and can cause significant property damage, but are less likely to result in serious injuries.

Flows: Flows are plastic or liquid movements in which mass (e.g. soil and rock) breaks up and flows during movement. Debris flows normally occur when a landslide moves down slope as a semi-fluid mass scouring, or partially scouring soils from the slope along its path. Flows are typically rapidly moving and also tend to increase in volume as they scour out the channel.