Erosion and Mass Erosion and Mass MovementsMovements

ErosionErosion Erosion causes the wearing away Erosion causes the wearing away

and lowering of Earth’s land and and lowering of Earth’s land and surface features as it transports surface features as it transports material away material away

The sun fuels the water cycle The sun fuels the water cycle and the forces of erosionand the forces of erosion

Triggers of Mass Movements

Mass MovementsMass Movements

Mass Movement: The transfer of rock and soil downslope due to gravity

Factors that trigger mass movements: • Water-saturated Surface• Over-steepening of Slopes• Lack of Vegetation• Earthquakes.

Types of Mass Movements

Mass MovementsMass Movements

Mass movements are classified on the kind of material that moves, how it moves, and the speed of movement.

Rockfalls/Debris Fall: When rocks or rock fragments fall freely through the air.

Types of Mass Movements

Mass MovementsMass Movements

• Speed: 1 mm/ day to 1 km/hr

Debris Flow: In a debris flow, a block of material moves suddenly along a flat, inclined surface

Heavy Rains Can Trigger Heavy Rains Can Trigger SlumpsSlumps

Types of Mass Movements

Mass MovementsMass Movements

•Mudflows

Flows include: Avalanches Mudflows Landslides

Types of Mass Movements

Mass MovementsMass Movements

Creep: the slow, downhill movement of soil

Soil Creep moves more material per year than any other mass movement- even though it is slow, it is constantly happening

*Creep can cause: Cracked roads, leaning utility poles, and bent trees