Erosion and Deposition: Wind, Gravity, and Living Things — Quiz
Question 7 • Earth and Space Science
A steep hillside above a rural village had remained stable for years. After a week of intense rainfall, the slope gave way, triggering a landslide that blocked nearby roads and damaged part of the landscape. Which condition most likely contributed to slope failure by altering the balance between resisting and driving forces?
Answer
A
Evaporation removed excess water and increased soil cohesion.
B
Tree roots stabilized the slope by anchoring surface soil.
C
Surface compaction reduced the likelihood of water penetration.
D
Water infiltration weakened internal friction and increased downslope force.
Explanation
Intense rainfall can infiltrate the hillside and saturate the soil. Added water increases the soil’s weight and can reduce friction between soil particles, making the downslope driving force greater than the forces resisting movement. Thus, water infiltration weakened internal friction and increased downslope force. The other choices describe conditions that would generally reduce the chance of slope failure.
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