( They ( ( suggest ( that ( ( the shift ) ( resulted ( in ( ( ( a change ) ( in ( ( the ( earth 's ) ) ( spin axis ) ) ) ) ( ( caused ( by ( ( a movement ) ( of mass ) ) ) ) ( either ( ( ( on or ) within ) ( the earth ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBP suggest) (SBAR (IN that) (S (NP (DT the) (NN shift)) (VP (VBD resulted) (PP (IN in) (NP (NP (DT a) (NN change)) (PP (IN in) (NP (NP (DT the) (NN earth) (POS 's)) (NN spin) (NNS axis))) (VP (VBN caused) (PP (IN by) (NP (NP (DT a) (NN movement)) (PP (IN of) (NP (NN mass))))) (PP (CC either) (IN on) (CC or) (IN within) (NP (DT the) (NN earth)))))))))) (. .)))
They suggest that the shift resulted in a change in the earth's spin axis caused by a movement of mass either on or within the earth.
(ROOT (S (NP (NP (DT The) (NN movement)) (PP (IN of) (NP (NP (DT an) (NN air) (NN mass)) (PP (IN over) (NP (NP (NN earth) (POS 's)) (NN surface)))))) (VP (VBZ causes) (NP (JJ local) (NN weather) (NNS changes))) (. .)))