( ( A tsunami ) ( ( is ( ( a ( ( fast moving ) ( ocean wave ) ) ) ( caused ( by ( an ( underwater earthquake ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN tsunami)) (VP (VBZ is) (NP (NP (DT a) (ADJP (JJ fast) (JJ moving)) (NN ocean) (NN wave)) (VP (VBN caused) (PP (IN by) (NP (DT an) (JJ underwater) (NN earthquake)))))) (. .)))
A tsunami is a fast moving ocean wave caused by an underwater earthquake.
(ROOT (S (NP (DT A) (-LRB- -LRB-) (NN n) (-RRB- -RRB-) (NN underwater) (NN earthquake)) (VP (VBZ creates) (NP (DT a) (NN tsunami))) (. .)))