1. Introduction to Mass Movement
Charity I. Mulig-Cruz

2. Definition Mass Movement (aka mass wasting)
Refers to the downslope movement of material under the direct influence of gravity.

3. Caution
“… although many people, including geologists, use the term (landslide), the word landslide has no specific definition in geology. Rather, it should be considered as a popular nontechnical term to describe all relatively rapid forms of mass wasting, including those in which sliding does not occur.” Earth Science by Tarbuck and Lutgens

4. Cause vs. Trigger of Mass Movement
Triggers
Controlling force of mass movement. There is only one cause – GRAVITY.
An event that initiates the downslope movement.
Not the sole cause of the mass wasting event, but just the last of many causes.

5. Triggers of Mass Wasting
Oversaturation of material with water
Torrential rain, melting of snow caps, over irrigation, leaking septic tanks
Over-steepening of slopes
Angle of inclination approaches (or is greater than) the angle of repose
Under-cutting, road excavation, mining
Overloading

6. Triggers of Mass Wasting
Removal of anchoring vegetation
Or replacement with vegetation with shallower root systems
Ground vibrations
Natural (earth quake and volcanic eruptions) and man-made (construction work and passing vehicles)

18. Factors Affecting Mass Wasting
Slope Angle/ Steepness of Slope
Weathering and Climate
Water Content
Vegetation
Geomorphology/ Nature and structure of slope materials

21. Classification of Mass Movement
Rate of Movement
Type of Movement
Materials
Rapid/ Fast
Slow
Fall
Slide
Flow
Creep
Solifluction
Rock
Debris
Soil