Many hill-slope masses are weak due to preexisting geologic conditions such as _______________.

Question

Quizplus · Accepted Answer

All of the choices (ancient slide surfaces, rock layering dipping less than topographic slopes, structures within the rocks such as fractures, ancient faults, and thin clay seams) can contribute to weak hill-slope masses. Ancient slide surfaces can create zones of weakness within the hill-slope, making them susceptible to future slides. Rock layering dipping less than topographic slopes can create planes of weakness within the rock mass, contributing to instability. Structures within the rocks such as fractures, ancient faults, and thin clay seams can also create planes of weakness, making hill-slopes more susceptible to mass wasting.

Many Hill-Slope Masses Are Weak Due to Preexisting Geologic Conditions