Japan Geoscience Union Meeting 2021

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[J] Oral

S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG49] Structure, evolution and deformation of island arcs associated with subduction processes

Fri. Jun 4, 2021 3:30 PM - 5:00 PM Ch.21 (Zoom Room 21)

convener:Masahiro Ishikawa(Graduate School of Environment and Information Sciences Yokohama National University), Masanao Shinohara(Earthquake Research Institute, University of Tokyo), Makoto MATSUBARA(National Research Institute for Earth Science and Disaster Resilience), Tatsuya Ishiyama(Earthquake Research Institute, University of Tokyo), Chairperson:Masanao Shinohara(Earthquake Research Institute, University of Tokyo), Tatsuya Ishiyama(Earthquake Research Institute, University of Tokyo)

4:15 PM - 4:30 PM

[SCG49-10] The fate of the Philippine Sea slab in central Japan

*Kazuki Miyazaki1, Junichi Nakajima1, Nobuaki Suenaga2, Shoichi Yoshioka2,3 (1.Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2.Research Center for Urban Safety and Security, Kobe University, 3.Faculty of Science, Graduate School of Science, Kobe University)


Keywords:Philippine Sea slab

The Philippine Sea slab beneath central Japan is believed to have started subducting at least 15Ma. Given a convergence rate of 3 cm/year, the Philippine Sea slab has subducted by 450 km. However, the slab shape determined by previous studies is shorter than the expectation. In this study, we explore the whereabouts of the subducted Philippine Sea slab using numerical calculations of slab subduction and seismic tomography.

The Philippine Sea slab is in contact with the Pacific slab beneath Kanto, and there is a possibility that the two oceanic slabs are interacting to form a complex shape. In this study, we used the numerical calculation program SSS (Torii and Yoshioka, 2007) to calculate the interaction of the Philippine Sea slab with the Pacific slab. When the Philippine Sea slab was subducted against the Pacific slab, which was prescribed as a highly viscous body, the subducted Philippine Sea slab was simulated either to lie on top of the Pacific slab or to bend in the opposite direction of the convergence. In the future, we will adjust the parameters to make the subduction calculation more realistic.

We plan to conduct seismic tomography in the Central Japan and compare the tomographic results with our calculations.