( But ( ( not ( all earthquakes ) ) ( ( occur ( at ( plate boundaries ) ) ) . ) ) )
(ROOT (S (CC But) (NP (RB not) (DT all) (NNS earthquakes)) (VP (VBP occur) (PP (IN at) (NP (NN plate) (NNS boundaries)))) (. .)))
But not all earthquakes occur at plate boundaries.
(ROOT (S (NP (NP (DT The) (JJ vast) (NN majority)) (PP (IN of) (NP (NN earthquake)))) (VP (VBZ occurs) (PRT (RP along)) (NP (NP (CD one)) (PP (IN of) (NP (NP (CD three) (NNS types)) (PP (IN of) (NP (NN plate) (NNS boundaries))))))) (. .)))