( It ( also ( ( issued ( ( ( ( warnings ( of ( possible tsunamis ) ) ) , ) or ) ( ( huge ( ocean waves ) ) ( that ( sometimes ( follow earthquakes ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (PRP It)) (ADVP (RB also)) (VP (VBD issued) (NP (NP (NP (NNS warnings)) (PP (IN of) (NP (JJ possible) (NNS tsunamis)))) (, ,) (CC or) (NP (NP (JJ huge) (NN ocean) (NNS waves)) (SBAR (WHNP (WDT that)) (S (ADVP (RB sometimes)) (VP (VBP follow) (NP (NNS earthquakes)))))))) (. .)))
It also issued warnings of possible tsunamis, or huge ocean waves that sometimes follow 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)))))) (. .)))