Which combination describes a high risk condition for landslides?

Which combination describes a high risk condition for landslides?

• A. Low angle slope, soil, and wet conditions
• B. High angle slope, soil, and wet conditions
• C. Low angle slope, rock, and wet conditions
• D. High angle slope, rock, and dry conditions

Answer: (B)

Landslide risk rises when three factors align: a steep slope, a loose, weathered material, and moisture. A high-angle slope increases the gravitational force trying to pull material downslope, so the driving force is strong. Soil, as opposed to solid rock, is more prone to sliding because it’s less cohesive and can include loose grains that easily rearrange. When that soil is wet, pore water pressure rises, which reduces the effective stress that holds the grains together. With lower shear strength and higher driving force, failure along the slope becomes much more likely. So, a combination of a steep slope, soil, and wet conditions creates a situation where the slope is both stressed and weakened, making a landslide much more probable than other scenarios.

Landslide risk rises when three factors align: a steep slope, a loose, weathered material, and moisture. A high-angle slope increases the gravitational force trying to pull material downslope, so the driving force is strong. Soil, as opposed to solid rock, is more prone to sliding because it’s less cohesive and can include loose grains that easily rearrange. When that soil is wet, pore water pressure rises, which reduces the effective stress that holds the grains together. With lower shear strength and higher driving force, failure along the slope becomes much more likely.

So, a combination of a steep slope, soil, and wet conditions creates a situation where the slope is both stressed and weakened, making a landslide much more probable than other scenarios.