( How ( ( ( do ( volcanic eruptions ) ) ( change ( the ( earth surface ) ) ) ) . ) )
(ROOT (SBARQ (WHADVP (WRB How)) (SQ (VBP do) (NP (JJ volcanic) (NNS eruptions)) (VP (VB change) (NP (DT the) (NN earth) (NN surface)))) (. .)))
How do volcanic eruptions change the earth surface.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN magma)) (VP (VBZ reaches) (NP (DT the) (NN surface)) (PP (IN through) (NP (NP (NNS cracks)) (PP (IN in) (NP (NP (DT the) (NN earth) (POS 's)) (NN crust)))))))) (, ,) (NP (DT a) (JJ volcanic) (NN eruption)) (VP (VBZ occurs)) (. .)))