( Yellowstone ( ( ( ( is ( famous ( for ( its ( volcanic activity ) ) ) ) ) , ) ( with ( ( geysers ( -- ( ( ( vents ( of steam ) ) ( created ( when ( ( underground magma ) ( ( ( heats ( the earth ) ) ( beneath groundwater ) ) ( until ( steam ( is ( forced ( explosively upward ) ) ) ) ) ) ) ) ) ) -- ) ) ) ( ( the best ) known ) ) ) ) . ) )
(ROOT (S (NP (NNP Yellowstone)) (VP (VBZ is) (ADJP (JJ famous) (PP (IN for) (NP (PRP$ its) (JJ volcanic) (NN activity)))) (, ,) (PP (IN with) (NP (NP (NNS geysers)) (PRN (: --) (NP (NP (NNS vents)) (PP (IN of) (NP (NN steam))) (VP (VBN created) (SBAR (WHADVP (WRB when)) (S (NP (JJ underground) (NN magma)) (VP (VBZ heats) (NP (DT the) (NN earth)) (PP (IN beneath) (NP (NN groundwater))) (SBAR (IN until) (S (NP (NN steam)) (VP (VBZ is) (VP (VBN forced) (S (ADJP (RB explosively) (JJ upward)))))))))))) (: --)) (NP (NP (DT the) (JJS best)) (VP (VBN known)))))) (. .)))
Yellowstone is famous for its volcanic activity, with geysers -- vents of steam created when underground magma heats the earth beneath groundwater until steam is forced explosively upward -- the best known.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN water)) (VP (VP (VBZ is) (VP (VP (VBN heated) (PP (IN by) (NP (NN magma)))) (CC and) (VP (VBZ makes) (NP (PRP$ its) (NN way)) (PP (TO to) (NP (DT the) (NN surface)))))) (CC and) (VP (VBZ creates))))) (NP (DT a) (-LRB- -LRB-) (NN n) (-RRB- -RRB-)) (VP (VBP geyser)) (. .)))