2026年5月28日(木) 09:00 〜 10:30 コンベンションホール (CH-B) (幕張メッセ国際会議場)

座長:石塚 治(産業技術総合研究所活断層火山研究部門)、赤松 祐哉(国立研究開発法人海洋研究開発機構)、Zhang Jin(Texas A&M University College Station)

This session focuses on two main topics: the oceanic plate as inputs to the subduction zone and the processes that initiate subduction. Subduction of oceanic plate drives various geodynamic phenomena, such as magma generation and fault formation, triggering volcanic and earthquake activity at subduction zones. Scales and distributions of such subduction zone-phenomena are controlled by physicochemical properties of subducting oceanic plates. In addition, oceanic plate-subduction processes transport surface materials such as water and carbon into the deep interior of Earth, playing an important role in global geochemical cycles. Physicochemical properties of oceanic plates as "subduction inputs" reflect their evolutionary histories from their formation at mid-ocean ridges until subduction at trenches. These characteristics are further modified by processes associated with plate bending prior to subduction, including fault development and petit-spot volcanism. Subduction initiation and the subsequent development of oceanic island arcs are poorly understood and remain an important unresolved problem in plate tectonics. Recent efforts to investigate geological record of subduction initiation along oceanic arcs and ophiolite have significantly improved understanding of processes associated with subduction initiation. This has also prompted extensive study utilizing tomography and numerical modeling to investigate requirements for the plate to subduct, and reconstruct tectonics for subduction initiation. We welcome contributions from a broad range of earth science (geophysics, geochemistry, geology, petrology, drilling science, and so on) discussing topics related to the nature of the subduction initiation of oceanic plate and their role as inputs to subduction zones.