( ( As ( ( ( the ( magma chamber ) ) ( below ( the mountain ) ) ) ( lost ( ( ( more and ) more ) ( of ( its contents ) ) ) ) ) ) ( , ( ( ( the ( mountain 's ) ) ( underlying support ) ) ( ( was ( ( ( ( weakened , ) ( causing ( ( the top ) ( of ( the ( peak ( to ( collapse ( into ( the ( magma chamber ) ) ) ) ) ) ) ) ) ) ) , ) ( creating ( ( the caldera ) ( known ( as ( Crater Lake ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (NP (DT the) (NN magma) (NN chamber)) (PP (IN below) (NP (DT the) (NN mountain)))) (VP (VBD lost) (NP (NP (JJR more) (CC and) (JJR more)) (PP (IN of) (NP (PRP$ its) (NNS contents))))))) (, ,) (NP (NP (DT the) (NN mountain) (POS 's)) (VBG underlying) (NN support)) (VP (VBD was) (VP (VBN weakened) (, ,) (S (VP (VBG causing) (NP (NP (DT the) (NN top)) (PP (IN of) (NP (DT the) (NN peak) (S (VP (TO to) (VP (VB collapse) (PP (IN into) (NP (DT the) (NN magma) (NN chamber))))))))))) (, ,) (S (VP (VBG creating) (NP (NP (DT the) (NN caldera)) (VP (VBN known) (PP (IN as) (NP (NNP Crater) (NNP Lake))))))))) (. .)))
As the magma chamber below the mountain lost more and more of its contents, the mountain's underlying support was weakened, causing the top of the peak to collapse into the magma chamber, creating the caldera known as Crater Lake.
(ROOT (S (PP (IN After) (NP (DT a) (JJ massive) (NN eruption))) (, ,) (NP (NP (DT a) (NN mountain)) (VP (VBG collapsing) (PP (IN above) (NP (DT an) (JJ empty) (NN chamber))))) (VP (MD will) (VP (VB create) (NP (DT a) (NN caldera)))) (. .)))