( ( Viscous ( ( -LRB- ( thick -RRB- ) ) magma ) ) ( ( ( ( produces ( volcanoes ( characterised ( by ( explosive eruptions ) ) ) ) ) , ) ( while ( ( non-viscous ( ( -LRB- ( runny -RRB- ) ) magma ) ) ( produce ( volcanoes ( ( characterised ( by ( effusive eruptions ) ) ) ( ( pouring ( ( large amounts ) ( of lava ) ) ) ( onto ( the surface ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Viscous)) (PRN (-LRB- -LRB-) (ADJP (JJ thick)) (-RRB- -RRB-)) (NNS magma)) (VP (VBZ produces) (NP (NP (NNS volcanoes)) (VP (VBN characterised) (PP (IN by) (NP (JJ explosive) (NNS eruptions))))) (, ,) (SBAR (IN while) (S (NP (JJ non-viscous) (PRN (-LRB- -LRB-) (NP (NNP runny)) (-RRB- -RRB-)) (NNS magma)) (VP (VBP produce) (SBAR (S (NP (NNS volcanoes)) (VP (VBD characterised) (PP (IN by) (NP (JJ effusive) (NNS eruptions))) (S (VP (VBG pouring) (NP (NP (JJ large) (NNS amounts)) (PP (IN of) (NP (NN lava)))) (PP (IN onto) (NP (DT the) (NN surface)))))))))))) (. .)))
Viscous (thick) magma produces volcanoes characterised by explosive eruptions, while non-viscous (runny) magma produce volcanoes characterised by effusive eruptions pouring large amounts of lava onto the surface.
(ROOT (S (NP (NP (DT The) (NN thickness)) (PP (IN of) (NP (NN magma)))) (VP (VBZ determines) (SBAR (IN whether) (S (NP (DT a) (JJ volcanic) (NN eruption)) (VP (MD will) (VP (VB be) (ADJP (JJ explosive))))) (CC or) (RB not))) (. .)))