( ( ( The volcanism ) ( of ( the Eifel ) ) ) ( ( is ( thought ( to ( be ( partly ( caused ( by ( ( ( the ( Eifel hotspot ) ) , ) ( ( a place ) ( where ( ( ( hot material ) ( from ( deep ( in ( the mantle ) ) ) ) ) ( ( rises ( ( ( ( ( to ( the surface ) ) , ) and ) partly ) ( by melt-ascent ) ) ) ( at ( ( deep fractures ) ( in ( ( the ( Earth 's ) ) crust ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN volcanism)) (PP (IN of) (NP (DT the) (NNP Eifel)))) (VP (VBZ is) (VP (VBN thought) (S (VP (TO to) (VP (VB be) (VP (ADVP (RB partly)) (VBN caused) (PP (IN by) (NP (NP (DT the) (JJ Eifel) (NN hotspot)) (, ,) (NP (NP (DT a) (NN place)) (SBAR (WHADVP (WRB where)) (S (NP (NP (JJ hot) (NN material)) (PP (IN from) (NP (NP (JJ deep)) (PP (IN in) (NP (DT the) (NN mantle)))))) (VP (VBZ rises) (PP (PP (TO to) (NP (DT the) (NN surface))) (, ,) (CC and) (RB partly) (PP (IN by) (NP (NN melt-ascent)))) (PP (IN at) (NP (NP (JJ deep) (NNS fractures)) (PP (IN in) (NP (NP (DT the) (NN Earth) (POS 's)) (NN crust))))))))))))))))) (. .)))
The volcanism of the Eifel is thought to be partly caused by the Eifel hotspot, a place where hot material from deep in the mantle rises to the surface, and partly by melt-ascent at deep fractures in the Earth's crust.
(ROOT (S (NP (NNS Rises)) (ADVP (RB then)) (VP (ADVP (RB sinks)) (VBZ does) (NP (NP (JJR deeper) (NN material) (NN cause) (NN convection)) (PP (IN in) (NP (DT the) (NN mantle))))) (. .)))