Which scenario is most likely to experience a landslide according to the factors listed?

Which scenario is most likely to experience a landslide according to the factors listed?

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

Answer: (D)

Stability of a slope depends on the balance between the driving force pulling material downslope and the resisting shear strength inside the slope. A steep slope increases the component of gravity that acts along the slope, boosting the driving force. Fractured rock creates natural planes of weakness where blocks can slide, lowering the resistance. Wet conditions raise pore-water pressure and lubricate fractures, further reducing effective stress and the material’s shear strength. When these three factors—high slope, fractured rock, and wet conditions—combine, the slope has both a stronger downslope push and weaker resistance, making a landslide most likely. The other scenarios either reduce the driving force, remove key weaknesses, or keep the material dry, which lowers the likelihood in comparison.

Stability of a slope depends on the balance between the driving force pulling material downslope and the resisting shear strength inside the slope. A steep slope increases the component of gravity that acts along the slope, boosting the driving force. Fractured rock creates natural planes of weakness where blocks can slide, lowering the resistance. Wet conditions raise pore-water pressure and lubricate fractures, further reducing effective stress and the material’s shear strength. When these three factors—high slope, fractured rock, and wet conditions—combine, the slope has both a stronger downslope push and weaker resistance, making a landslide most likely. The other scenarios either reduce the driving force, remove key weaknesses, or keep the material dry, which lowers the likelihood in comparison.