Why Might the Infiltration of Water Deep into a Slide

Multiple Choice

Why might the infiltration of water deep into a slide mass increase landslide hazards?

A) Deep infiltration forces vegetation to root more deeply.
B) Water will erode the subsurface materials, reducing strength of the slide mass.
C) Water in the deep subsurface influences soil formation, leading to shallow soil slips.
D) The water increases the pore water pressure, effectively lifting the slide mass from stable ground beneath.