( ( ( ( ( ( Tidal waves ) , ) or ) ( tsunamis ( as ( they ( ( are properly ) termed ) ) ) ) ) , ) ( ( are ( created ( by ( an ( underwater ( seismic event ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Tidal) (NNS waves)) (, ,) (CC or) (NP (NP (NNS tsunamis)) (SBAR (IN as) (S (NP (PRP they)) (VP (VBP are) (ADVP (RB properly)) (VP (VBN termed)))))) (, ,)) (VP (VBP are) (VP (VBN created) (PP (IN by) (NP (DT an) (JJ underwater) (JJ seismic) (NN event))))) (. .)))
Tidal waves, or tsunamis as they are properly termed, are created by an underwater seismic event.
(ROOT (S (NP (DT A) (-LRB- -LRB-) (NN n) (-RRB- -RRB-) (NN underwater) (NN earthquake)) (VP (VBZ creates) (NP (DT a) (NN tsunami))) (. .)))