Uyeda and Kanamori (1979) classified subduction zones into two modes - Mariana type and Chilean type. Many features such as back-arc basin, stress field, dip angle of Benioff-Wadati zone, thrust earthquake and accretionary prism are different in both types. Kinds of stress field as well as the dip angle of Benioff-Wadati zone are important factors controlling the spatial distribution of volcanic activity. Mariana type represents tensional field and high dip angle, whereas Chilean type does compressional and gentle dip. From the relationship between the dip angle of Benioff-Wadati zone and volcanic spacing, it is recognized that as the dip steepens the linear density of volcanoes increases but the width of them decreases. As the dip angle increases, the stress field becomes more tensional and volcanic magmas rise more actively, Also, the dip angle has a close relation to the dip of partial melting zone located along the subducting slab. As the dip increases, the width of partial melting zone decreases and subsequently the spacing of volcanoes decreases. Volcanic rocks in the subduction zone represent geochemical differences due to the mode of subduction and degree of arc maturity. In continental arc and mature island arc (Chilean type) the volcanic rocks show the geochemical variation from tholeiitic to calc-alkaline and finally to alkaline, whereas in immature arc without continental crust (Mariana type) they generally show tholeiitic affinities. However, in addition to the inter-type differences in tectonic environments and geochemical natures, the infra-type ones are also prominent. It seems like that the change of evolutionary step in each type has caused the intra-type differences.

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