( However ( , ( earthquakes ( ( ( occur ( in ( ( the middle ) ( of plates ) ) ) ) ( as well ) ) . ) ) ) )
(ROOT (S (ADVP (RB However)) (, ,) (NP (NNS earthquakes)) (VP (VBP occur) (PP (IN in) (NP (NP (DT the) (NN middle)) (PP (IN of) (NP (NNS plates))))) (ADVP (RB as) (RB well))) (. .)))
However, earthquakes occur in the middle of plates as well.
(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)))))) (. .)))