- is the down slope movement of earth materials under the influence of gravity. The detachment and movement of earth materials occurs if the stress imposed is greater than the strength of the material to hold it in place. - Mass movement is a naturally occurring process that contributes to the cycle of tectonic uplift, erosion, transportation, and deposition of sediments. They are responsible for the topography of mountain ranges and river canyons that has developed over geologic time.
Types of mass wasting:
A. Slide involves movement of coherent blocks of material along a well-defined surface 1. Rockslide
• Also called debris slides or "landslides". Occurs when blocks of rock, or masses of unconsolidated material slide down a slope. These are among the most destructive of mass movements. May be triggered by rain or melting snow, or earthquakes. 2. Slump
• Slumps involve a mass of soil or other material sliding along a curved, rotational surface. (Shaped like a spoon.) Slumps are sometimes seen along interstate highways where the graded soil on the sides of the road is a little too steep. 3. Creep
• A SLOW downhill movement of soil and regolith. Creep results in tree trunks that are curved at the base, tilted utility poles, fence posts, and tombstones, and causes retaining walls to be broken or overturned. B. Fall involves free fall of material (no contact with any surface except to bounce)
-The free fall of detached pieces of material of any size; may fall directly downward or bounce and roll. May occur as result of freeze-thaw, or the loosening action of plant roots. Causes the formation of talus slopes. Signs along highways warn of rolling rock in mountainous areas where the road has been cut into the hillside.
C. Flow involves continuous movement of material as a viscous fluid 1. Debris flow or mudflow
• Commonly occur in...