Mass Wasting Event

Erosion

The movement of weathered materials from one location to another by agents such as water, wind, glaciers and gravity.

Deposition

Occurs when sediments are laid down on the ground or sink to the bottom of a body of water

What are the 2 Main Agents of Erosion?

Gravity and Running Water

What are the main types of Erosion?

Water, Wind, Glaciers, Plants, Humans, Animals, and Gravity

Mass Movement/Wasting

Transfer of rock, soil and debris down slope due to gravity and other forces.

What produces landforms?

Weathering and mass wasting

Triggers of Mass Movement/Wasting

Saturation of surface materials, over-steepening of slopes, removal of vegetation, and earthquakes

How do slopes get over steepened?

Human activity and erosion

How do Geologists classify mass movement?

On the kind of material that moves, resistance to flow, density, how it moves, speed of movement, and the amount of water.

Angle of Repose

Indicates an unconsolidated material’s resistance to sliding

What forms gentle slopes?

Fine, rounded sand

What forms steep slopes?

Coarse, angular sand

What forms steep talus slopes?

Angular boulders

Where does mass movement often occur?

Along planes of weakness

What are the kinds of mass wasting?

Rockfalls, slides, slumps, flows, and a creep

Rockfalls

Free falling rocks that can trigger other mass movements

Slides

A block of material moves suddenly along flat inclined surface

Slump

Downward movement along a curved surface that doesn’t travel fast and leaves crescent shaped cliff face on the surface 

Flow

Usually contain large amounts of water that follow the contour of the land and takes everything with it

Creep

Slowest mass movement, freeze/thaw contribute, with an easily recognizable tilting effect it has on structures, trees, objects, and walls.

How do you prevent mass wasting events?

Identify problem areas, improve drainage, improve dip slopes, identify possible hazard areas, avalanche protection structures, install rock bolts, etc.