( There ( ( are ( ( two types ) ( of ( seismic waves ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD two) (NNS types)) (PP (IN of) (NP (JJ seismic) (NNS waves))))) (. .)))
There are two types of seismic waves.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD two) (NNS types)) (PP (IN of) (NP (NN surface) (NNS waves))))) (. .)))