( ( Subsea earthquakes ) ( ( may ( produce ( ( ( ( ( ( a tsunami ) , ) or ) ( a ( seismic ( sea wave ) ) ) ) , ) ( which ( may ( arrive ( ( onshore as ) ( a ( huge ( ` ( tidal ( ' wave ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Subsea) (NNS earthquakes)) (VP (MD may) (VP (VB produce) (NP (NP (NP (DT a) (NN tsunami)) (, ,) (CC or) (NP (DT a) (JJ seismic) (NN sea) (NN wave)) (, ,)) (SBAR (WHNP (WDT which)) (S (VP (MD may) (VP (VB arrive) (NP (NP (NN onshore)) (IN as) (NP (DT a) (JJ huge) (`` `) (JJ tidal) ('' ') (NN wave)))))))))) (. .)))
Subsea earthquakes may produce a tsunami , or a seismic sea wave, which may arrive onshore as a huge 'tidal' wave.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NP (DT the) (NN energy)) (PP (IN of) (NP (DT the) (NN earthquake)))) (VP (VBZ reaches) (VP (NN shore))))) (, ,) (NP (PRP it)) (VP (VBZ forms) (SBAR (S (NP (DT a) (JJ huge) (NN wave)) (VP (VBD called) (NP (DT a) (NN tsunami)))))) (. .)))