Mass Movements Flashcards
Gravity’s 2 components
Surface parallel component “D”: parallel to gravity’s force.
Surface Perpendicular Component “N”: produces friction “F” which resists downward force of “D”
If F>D then the object is stable
Creep
is the gravitational process of things being pulled downward.
Angle of repose
is the angle to which you can stack something before it becomes unstable.
The formula for energy is=
PE=MGH
External and Internal causes of mass movement
External: increase of mass on slope, the steeping of the slope and removal of support
Internal: is weathering and the adverse of geological structure.
External and internal role of water
External: rainfall increases erosion, water-based undercutting of slopes occurs.
Internal: additional weight is added, decreased cohesion through an increase in pore water pressure. The dissolution of the material.
3 Types of movement
fall, slide, and flow
Plot mudflow, earthflow, landslide, slump, rockfall in terms of speed and moisture
MUDFLOW = WET AND FAST EARTH FLOW= WET AND SLOWER LANDSLIDE= MEDIUM AND FAST SLUMP= MEDIUM AND SLOW ROCKFALL= DRY AND FAST
Mitigation for mass movement focuses on?
reshaping the topography by:
focusing on reducing gravity and loose material
increasing cohesion and the shear strength (resistance)
controlling water content and erosion through warning systems
diversion and containment through barriers
Shear force, shear strength, normal force
the normal force is equal to the gravity pulling it down
the shear strength is looking to resist
the shear force wants to follow the direction of gravity on the slope.
Slope is the product of what features
Uplift + Erosion
what besides gravity causes creep
freeze and thaw
what causes slump
excess water in thick unconsolidated deposits
