( ( Subduction ( zone earthquakes ) ) ( ( occur ( when ( there ( ( is motion ) ( ( ( between ( the ( two plates ) ) ) ( rather than ) ) ( at ( localized faults ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Subduction) (NN zone) (NNS earthquakes)) (VP (VBP occur) (SBAR (WHADVP (WRB when)) (S (NP (EX there)) (VP (VBZ is) (NP (NN motion)) (PP (PP (IN between) (NP (DT the) (CD two) (NNS plates))) (CONJP (RB rather) (IN than)) (PP (IN at) (NP (VBN localized) (NNS faults)))))))) (. .)))
Subduction zone earthquakes occur when there is motion between the two plates rather than at localized faults.
(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)))))) (. .)))