( Earthquakes ( ( ( ( occur ( ( ( at or ) near ) ( plate boundaries ) ) ) , ) ( where ( ( the plates ) ( ( ( ( ( ( spread apart ) , ) collide ) , ) or ) ( slide ( past ( one another ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Earthquakes)) (VP (VBP occur) (PP (IN at) (CC or) (IN near) (NP (NN plate) (NNS boundaries))) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (DT the) (NNS plates)) (VP (VP (VB spread) (ADVP (RB apart))) (, ,) (VP (VB collide)) (, ,) (CC or) (VP (VB slide) (PP (IN past) (NP (CD one) (DT another)))))))) (. .)))
Earthquakes occur at or near plate boundaries, where the plates spread apart, collide, or slide past one another.
(ROOT (S (NP (NP (CD Two) (NNS plates)) (VP (VBG sliding))) (VP (MD can) (VP (VB increase) (NP (NP (DT the) (NN occurance)) (PP (IN of) (NP (NNS earthquakes)))))) (. .)))