( Calderas ( ( form ( as ( ( a result ) ( of ( collapse ( of ( an ( underlying ( magma chamber ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Calderas)) (VP (VBP form) (PP (IN as) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (NP (NN collapse)) (PP (IN of) (NP (DT an) (VBG underlying) (NN magma) (NN chamber)))))))) (. .)))
Calderas form as a result of collapse of an underlying magma chamber.
(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)))) (. .)))