Subduction of the Philippine Sea plate beneath southwestern Japan: Slab geometry and its relationship to arc magmatism

Junichi Nakajima, Akira Hasegawa

研究成果: Article査読

147 被引用数 (Scopus)

抄録

We carry out high-resolution three-dimensional seismic tomography of the crust and upper mantle beneath southwestern (SW) Japan using arrival-time data obtained from the nationwide seismograph network. The tomographic images provide new insights into the configuration of the Philippine Sea slab and arc magmatism. The results confirm the existence of an aseismic portion of the Philippine Sea slab at greater depths beyond the seismic portion. The Philippine Sea slab is subducting aseismically down to at least a depth of 200 km in Chubu, 60-80 km in Kinki, and 60 km in Chugoku and is subducting seismically to depths of 150-200 km in Kyushu. In the Chubu district, it is subducting seismically at a shallow dip and then bends downward beneath the volcanic area, whereas in the Kinki district, it is subducting subhorizontally as far as the Japan Sea. The differences in the slab geometry between adjacent regions correlate with the differences in volcanic activity, suggesting the importance of the geometry of the Philippine Sea slab on arc magmatism. Our tomographic images further imply subduction of the Philippine Sea slab down to a depth of around 70 km northwest of the Izu Peninsula. The Philippine Sea slab in that region might have split into western and eastern parts separated by a slab tear and collided with the Pacific slab at depths of 150-200 km.

本文言語English
論文番号B08306
ジャーナルJournal of Geophysical Research: Solid Earth
112
8
DOI
出版ステータスPublished - 2007 8 4

ASJC Scopus subject areas

  • 地球物理学
  • 地球化学および岩石学
  • 地球惑星科学(その他)
  • 宇宙惑星科学

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