Japan Geoscience Union Meeting 2016

Presentation information


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

[S-CG62] Activation of long-term volcanic activity by mega-earthquake

Mon. May 23, 2016 1:45 PM - 3:15 PM 201A (2F)

Convener:*Eiichi Takahashi(Earth and Planetary Sciences, Graduate School of Science and Technology, Tokyo Institute of Technology), Mitsuhiro Nakagawa(Department of Natural History of Science, Faculty of Science, Hokkaido University), Kenji Satake(Earthquake Research Institute, University of Tokyo), Mie Ichihara(Earthquake Research Institute, University of Tokyo), Nobuo Geshi(Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology), Chair:Morihisa Hamada(国立研究開発法人海洋研究開発機構地球内部物質循環研究分野)

2:15 PM - 2:30 PM

[SCG62-09] Deep seismic structure beneath volcanic arcs

*Junichi Nakajima1 (1.Department of Earth and Planetary Sciences, Tokyo Institute of Technology)

Keywords:volcano, Tohoku, upwelling flow

The subduction zone system on the Earth is over 40,000 km long. The active processes –brittle deformation, metamorphism, convection and volcanism– beneath volcanic arcs are all linked with slab-derived fluids. Here I review seismological observations in subduction zones and show that a low-velocity zone is observed in the mantle wedge beneath all volcanic arcs. Interestingly, geometries of the low-velocity zone, however, vary depending on the dip and age of the subducting slab. I also present deep crustal structure in NE Japan and discuss how the crustal structure changes along the volcanic front, providing a clue to understand deep origins of arc magmas and ongoing processes beneath volcanic arcs.