著者

高橋 正樹

出版者

特定非営利活動法人日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.39, no.4, pp.207-218, 1994-09-20

被引用文献数

4

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Late Quaternary poly genetic volcanoes in Japanese islands can be classified into two types : P-type and O-type. The vent of the P-type (parallel types) aligns in parallel with the orientation of regional σ_<Hmax>, while the vent alignment of the O-type (oblique type) is normal or highly oblique to it. The P-type consists of three sub-types based on the kind of associated active faults : PN (with normal faults), PS (with strike-slip faults), and PR (with reverse faults). Most of the O-type are constructed on the mountain range which is bounded on both side with reverse faults ; its vent alignment is probably controlled by the local extensional stress field in the mountain mass caused by the gravity tectonics. Thin sheet-like magma chambers are estimated to be present beneath the O-type volcanoes ; the arrangement of maximum principal stress axis producing reverse faults (σ_v=σ_3) favors the formation of sheet-like magma chambers. The eruption rate of the O-type is generally small because of the complexity of its magma plumbing system.