How Have People Contributed to Landslide Problems

How have people contributed to landslide problems?

A) Houses add weight to slopes, increasing driving forces for the slope to fail.
B) Excavation may locally steep slopes, interrupting normal drainage patterns.
C) Septic systems or leaking water pipes add fluid to the slope.
D) Clearing vegetation with deep roots decreases the slope's resisting forces.
E) all of the above