1. Mass Movement

2. Triggers of Mass Movement
Mass movement is the transfer of rock and soil downslope due to gravity
Factors that commonly trigger mass movements are:
Saturation of surface materials with water
Oversteepening of slopes
Removal of vegetation
Earthquakes

3. Types of Mass Movements
Geologists classify mass movements based on the kind of material that moves, how it moves, and the speed of movement
Six types of mass movement include:
Rock falls
Slides
Slumps
Mudflows
Earthflows
Creep

4. Rock Falls
What moves: A rockfall occurs when rocks or rocks fragments fall freely through the air
How it moves: Slopes that are too steep to hold loose material on the surface
Speed of movement: Any speed
Other: Result from frost action, triggers other mass movements

5. Slides
What moves: A block of material moves suddenly along a flat, inclined surface
How it moves: Occurs on high mountain areas
Speed of movement: Fast
Other: Triggered by rain or melting snow

6. Slumps
What moves: The downward movement of a block of material along a curved surface
How it moves: Upper part tilts back, leaving a crescent-shaped cliff
Speed of movement: Slow over a short distance
Other: Triggered by heavy rain

7. Slump

8. Mudflow
What moves: A mixture of soil, rock, and water that has a consistency of wet concrete moves downslope
How it moves: Heavy downpour will cause flows
Speed of movement: Quickly
Other: Very dangerous in populated areas

9. Earthflows
What moves: The downslope movement of water-saturated, clay-rich sediment
How it moves: Occurs on hillsides in humid regions
Speed of movement: Slow

10. Creep What moves: The downhill movement of soil and regolith
How it moves: Freeze-thaw cycles
Speed of movement: Extremely slow
Other: Can move fences, crack walls and underground pipes