( ( ( ( The waves ) ( generated ( by earthquakes ) ) ) ( -LRB- ( ( seismic waves ) -RRB- ) ) ) ( ( allow ( us ( to ( study ( the ( Earth ( s interior ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS waves)) (VP (VBN generated) (PP (IN by) (NP (NNS earthquakes)))) (PRN (-LRB- -LRB-) (NP (JJ seismic) (NNS waves)) (-RRB- -RRB-))) (VP (VBP allow) (S (NP (PRP us)) (VP (TO to) (VP (VB study) (NP (DT the) (NNP Earth) (NNP s) (NN interior)))))) (. .)))
The waves generated by earthquakes (seismic waves) allow us to study the Earth s interior.
(ROOT (S (NP (NP (NNS Studies)) (PP (IN of) (NP (NN earthquake) (NNS waves)))) (VP (VBP have) (VP (VBN helped) (S (NP (NNS scientists)) (VP (VB determine) (NP (NP (DT the) (NN structure)) (PP (IN of) (NP (NP (NN earth) (POS 's)) (NN interior)))))))) (. .)))
Studies of earthquake waves have helped scientists determine the structure of earth's interior.