Landslip

Landslip, often used interchangeably with landslide, is a form of mass wasting in which a coherent block of earth, rock, or debris moves downslope under gravity. In British practice landslip can refer to both rapid slides and slow, creeping movements, and covers several modes of failure, including translational slides and rotational slides (slumps).

Movement occurs along a slip surface that can be planar, curved, or irregular. The moving mass may be intact or fragmented and often includes soil, weathered rock, and vegetation. Speed ranges from imperceptible creep to sudden, destructive failures that can reach several meters per second.

Causes include high pore-water pressures from prolonged rainfall or rapid snowmelt, changes in groundwater, seismic shaking, and volcanic activity. Human actions such as deforestation, road cutting, excavation, underground mining, and reservoir loading can destabilize slopes and trigger landslips.

Indicators include ground cracking, tilting of structures, bulging toes at the base of a slope, surface seeps, springs, and unexpected ground deformation. Monitoring methods include field surveys, inclinometers, piezometers, and remote sensing.

Impacts can be severe, including damage to buildings, roads, pipelines, and utilities; injury or loss of life; and disruption of transportation and drainage. Mitigation focuses on slope stabilization and drainage control through proper design, retaining structures, soil nailing, revegetation, terracing, and early warning systems.

Worldwide, landslips are a major natural hazard, with hazard assessments and land-use planning used to reduce risk. The term landslip is more common in the U.K. and Commonwealth, while landslide is widely used elsewhere.