( ( ( ( ( ( The ( steep-walled crater ) ) ( is ( ( ( ( 700 metres ) wide ) and ) ( ( 200 meters ) deep ) ) ) ) , ) and ) ( ( lava flows ) ( ( extend along ) ( ( the ( eastern half ) ) ( of ( the island ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT The) (JJ steep-walled) (NN crater)) (VP (VBZ is) (ADJP (ADJP (NP (CD 700) (NNS metres)) (JJ wide)) (CC and) (ADJP (NP (CD 200) (NNS meters)) (JJ deep))))) (, ,) (CC and) (S (NP (NN lava) (NNS flows)) (VP (VBP extend) (PRT (RP along)) (NP (NP (DT the) (JJ eastern) (NN half)) (PP (IN of) (NP (DT the) (NN island)))))) (. .)))
The steep-walled crater is 700 metres wide and 200 meters deep, and lava flows extend along the eastern half of the island.
(ROOT (S (NP (DT The) (JJ photic) (NN zone)) (VP (VBZ extends) (ADJP (NP (CD 200) (NNS meters)) (JJ deep))) (. .)))
The photic zone extends 200 meters deep.