1. Hazardous Environments resulting from Mass Movements

2. Shear stress> shear strength
Mass movements take place when shear stress (the force trying to move the material) is greater than shear strength (the strength or resistance of the slope).
Shear stress> shear strength

3. Causes of Mass Movement
Movement is determined by:
Gravity
Slope angle
Pore pressure

4. Hazardous mass movements
Landslides
Mudslides
Avalanches

5. landslides Triggered by Seismic activity Heavy rainfall Human activity
Case studies of the Caribbean
Case study of Puerto Rico
Case study of China

15. mudslides Triggered by
Human causes – uncontrolled building, creation of impermeable surfaces, deforestation, burning.
Heavy rainfall
Tectonic activity
Case studies – Italy 1998, Venezuela

27. avalanche Mass movement of ice and snow Triggered by:
Newly fallen snow falling off older snow
Partially thawed snow in spring
Steep slopes
North-facing slopes (NH)

28. Classification of avalanche:
Type of breakaway
Position of sliding surface
Water content
Form of avalanche – open or channelled.
Case studies – Europe 1999.