( ( ( Landslides and ) ( Landslide ( Susceptibility Landslides ) ) ) ( ( are ( caused ( when ( ( ( the force ) ( of gravity ) ) ( ( pulls ( rock ( , ( ( debris or ) soil ) ) ) ) ( down ( a slope ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Landslides)) (CC and) (NP (NNP Landslide) (NNP Susceptibility) (NNP Landslides))) (VP (VBP are) (VP (VBN caused) (SBAR (WHADVP (WRB when)) (S (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NN gravity)))) (VP (VBZ pulls) (NP (NN rock) (, ,) (NN debris) (CC or) (NN soil)) (ADVP (RB down) (NP (DT a) (NN slope)))))))) (. .)))
Landslides and Landslide Susceptibility Landslides are caused when the force of gravity pulls rock, debris or soil down a slope.
(ROOT (S (NP (NNP Gravity)) (VP (VBZ causes) (S (NP (NNS rocks)) (VP (TO to) (VP (VB roll) (ADVP (RB downhill)))))) (. .)))