Fall
This is generally characterised by a rapid to extremely rapid rate of movement with the descent of material characterised by a freefall period. Falls are commonly triggered by earthquakes or erosion processes.
Topple
This is characterised by the tilting of rock without collapse, or by the forward rotation of rocks about a pivot point. Topples have a rapid rate of movement and failure is generally influenced by the fracture pattern in rock. Material descends by abrupt falling, sliding, bouncing and rolling.
Flow
This is the most destructive and turbulent form of landslide. Flows have a high water content which causes the slope material to lose cohesion, turning it into a slurry. They are channelled by the landscape and move rapidly.
Slide
This is one of the most common forms of failure and can be subdivided into translational and rotational slides. Rotational slides are sometimes called slumps because they move with rotation. Translational slides have a planar, or two dimensional surface of rupture. Slides are most common when the toe of the slope is undercut. They have a moderate rate of movement and the coherence of material is retained, moving largely intact or in broken pieces.
Spread
This phenomenon is characterised by the gradual lateral displacement of large volumes of distributed material over very gentle or flat terrain. Failure is caused by liquefaction which is the process when saturated loose sediment with little or no cohesion such as sands or silts are transformed into a liquid-like state. This process is triggered by rapid ground motion most commonly during earthquakes.
This is generally characterised by a rapid to extremely rapid rate of movement with the descent of material characterised by a freefall period. Falls are commonly triggered by earthquakes or erosion processes.
Topple
This is characterised by the tilting of rock without collapse, or by the forward rotation of rocks about a pivot point. Topples have a rapid rate of movement and failure is generally influenced by the fracture pattern in rock. Material descends by abrupt falling, sliding, bouncing and rolling.
Flow
This is the most destructive and turbulent form of landslide. Flows have a high water content which causes the slope material to lose cohesion, turning it into a slurry. They are channelled by the landscape and move rapidly.
Slide
This is one of the most common forms of failure and can be subdivided into translational and rotational slides. Rotational slides are sometimes called slumps because they move with rotation. Translational slides have a planar, or two dimensional surface of rupture. Slides are most common when the toe of the slope is undercut. They have a moderate rate of movement and the coherence of material is retained, moving largely intact or in broken pieces.
Spread
This phenomenon is characterised by the gradual lateral displacement of large volumes of distributed material over very gentle or flat terrain. Failure is caused by liquefaction which is the process when saturated loose sediment with little or no cohesion such as sands or silts are transformed into a liquid-like state. This process is triggered by rapid ground motion most commonly during earthquakes.