( Seismologists ( ( ( ( study ( ( the ( ( location and ) force ) ) ( of earthquakes ) ) ) and ) ( ( trace ( ( the behavior ) ( of ( earthquake waves ) ) ) ) ( to ( interpret ( ( the structure ) ( of ( the Earth ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Seismologists)) (VP (VP (VB study) (NP (NP (DT the) (NN location) (CC and) (NN force)) (PP (IN of) (NP (NNS earthquakes))))) (CC and) (VP (VB trace) (NP (NP (DT the) (NN behavior)) (PP (IN of) (NP (NN earthquake) (NNS waves)))) (S (VP (TO to) (VP (VB interpret) (NP (NP (DT the) (NN structure)) (PP (IN of) (NP (DT the) (NN Earth))))))))) (. .)))
Seismologists study the location and force of earthquakes and trace the behavior of earthquake waves to interpret the structure of the Earth.
(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.