7.5E| Landslide Triggers and Home Locations

Overview

Mass wasting, a.k.a. landslides, happen when the force of gravity exceeds the frictional forces holding the slope material (soil, regolith, or bedrock) in place. Oftentimes, slopes are at or have exceeded their angle of repose and a trigger to start the slope failure. Common triggers include:

• water, usually from heavy rain (water adds weight to the slope and reduces friction)
• removal of vegetation (vegetation binds soil together and slows the rate at which rainwater infiltrates a slope)
• oversteepening slope, so it exceeds its angle of repose (oversteepening can be caused by tectonic uplift, erosion, and construction of roads, homes, etc.)
• planes of weakness that are parallel to the slope above (these make natural slip surfaces, especially if the plane contains clay)

Instructions

Complete the previous assignments in this module and read the information in the overview above.

Read each question and analyze each image. Apply what you've learned to choose the best answer. 

Note: If you find that you need extra support in accessing any items in this quiz, please notify me via email right away so I can offer you an alternative.

Time Needed

About 15 minutes. 

Learning Objectives

• Use material and motion to classify a mass-wasting event
• Identify different forms of mass wasting and correlate different triggers with real-life mass wasting events