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Define mass movement and its classification

Short answer

Mass movement is the downslope movement of soil, rock or debris under gravity alone. Varnes classifies it by movement type (fall, topple, slide, spread, flow, complex) and material (rock, debris, earth).

Define mass movement. Describe its types (classification system of mass movement by Varnes).

Mass movement is the downslope movement of soil, rock or debris under gravity, without a flowing medium like a river or glacier carrying it.

Varnes classification (1978) is based on the type of movement and the material (rock, debris, earth):

MovementRockSoil (debris / earth)
FallRock fallDebris fall, earth fall
ToppleRock toppleDebris / earth topple
Slide: rotationalRock slumpSlump
Slide: translationalPlanar / wedge slide, block slideDebris slide, earth slide
Lateral spreadRock spreadEarth spread
FlowRock avalancheDebris flow, earth flow, mud flow, creep
ComplexCombination of two or more types
  • Fall: free fall of detached blocks from a steep face.
  • Topple: forward rotation of a block about a lower point.
  • Slide: movement along one or more slip surfaces (rotational or translational).
  • Spread: extension of a soil or rock mass above a softer layer.
  • Flow: the mass moves like a viscous fluid, often water-saturated.
  • Creep: very slow, continuous movement.

✓ Answer checked by Claude Opus 5.5 (high effort)

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