Mon. Apr 28, 2014 9:00 AM - 10:35 AM 414 (4F)

Convener:*Simon Wallis(Department of Earth and Planetary Sciences, Nagoya University), Yoshihiro Hiramatsu(School of Natural System, College of Science and Engineering, Kanazawa University), Ken-ichi Hirauchi(Department of Geosciences, Graduate School of Science, Shizuoka University), Tomoyuki Mizukami(Earth Science Course, School of Natural System, College of Science and Engineering, Kanazawa University), Chair:Simon Wallis(Department of Earth and Planetary Sciences, Nagoya University), Ken-ichi Hirauchi(Department of Geosciences, Graduate School of Science, Shizuoka University)

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.