Session outline

Solid Earth Sciences(S) Session Sub Category Science of the Earth's Interior & Tectonophysics(IT) Session ID S-IT04 Title Fluid flow, deformation and physical properties of the subduction boundary and forearc mantle Short title Fluid and dynamic processes in forearc Convener Name Simon Wallis Affiliation Department of Earth and Planetary Sciences, Nagoya University Co-convener 1. Name Yoshihiro Hiramatsu Affiliation School of Natural System, College of Science and Engineering, Kanazawa University Co-convener 2. Name Ken-ichi Hirauchi Affiliation Department of Geosciences, Graduate School of Science, Shizuoka University Co-convener 3. Name Tomoyuki Mizukami Affiliation Earth Science Course, School of Natural System, College of Science and Engineering, Kanazawa University International Symposium 'International Symposium' in addition to Scientific session. Language English Scope Subduction brings oceanic crustal material into direct contact with the overlying mantle wedge. The subduction boundary changes its slip behaviour from seismic to aseismic with increasing depth. The deep forearc region around the tip of mantle wedge shows a transitional nature with episodic tremor and slip which are probably strongly influenced by sustained fluid flow. The amount of fluid release in the forearc is not well constrained but is thought to depend on the thermal structure of the subduction zone. Fluid released into the forearc mantle will cause a transformation of mantle rock to serpentinite. This metamorphic transformation implies a major volume change and a change in physical properties of the mantle. Despite considerable recent advances in understanding these processes, there is no good consensus on how strong this forearc region is likely to be or how fluids are transported. Such information is vital in developing more complete tectonic models of these geologically and geophysically important regions. In this session we aim to contribute to our understanding of the deep forearc by bringing together the results of a variety of different approaches including field based observations, experimental work, theoretical modeling and geophysical observations on deformation, reaction and physical properties in fluid-rock systems. Type of presentation Oral and Poster presentation Invited papers Shoichi Yoshioka (Kobe Uni.) Atsushi Okamoto (Tohoku Uni.) Keishi Okazaki (Brown Uni.) Ikuko Wada (Tohoku University) Kazushige Obara (Tokyo Uni.)