( Tsunamis ( ( are ( waves ( formed ( when ( ( ( huge masses ) ( of water ) ) ( are ( displaced ( by ( ( ( undersea ( volcanic eruptions ) ) or ) earthquakes ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Tsunamis)) (VP (VBP are) (NP (NP (NNS waves)) (VP (VBN formed) (SBAR (WHADVP (WRB when)) (S (NP (NP (JJ huge) (NNS masses)) (PP (IN of) (NP (NN water)))) (VP (VBP are) (VP (VBN displaced) (PP (IN by) (NP (NP (JJ undersea) (JJ volcanic) (NNS eruptions)) (CC or) (NP (NNS earthquakes))))))))))) (. .)))
Tsunamis are waves formed when huge masses of water are displaced by undersea volcanic eruptions or earthquakes.
(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)))))) (. .)))