Japan Geoscience Union Meeting 2014

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Oral

Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS24_28PM2] Geophysical fluid dynamics-Transfield approach to geoscience

Mon. Apr 28, 2014 4:15 PM - 5:45 PM 313 (3F)

Convener:*Keita Iga(Atmosphere and Ocean Research Institute, The University of Tokyo), Kensuke Nakajima(Department of Earth and Planetary Sciences,Flculty of Sciences,Kyushu University), Shigeo Yoshida(Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University), Takatoshi Yanagisawa(Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology), Hidenori Aiki(Japan Agency for Marine-Earth Science and Technology), Chair:Shigeo Yoshida(Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University)

4:30 PM - 4:45 PM

[MIS24-12] Heater size effect on generation of thermal plumes

*Ichiro KUMAGAI1, Yasuko YAMAGISHI2 (1.Meisei University, 2.IFREE, JAMSTEC)

Keywords:plume, mantle, fluid dynamics, experiment

Mantle plumes from the CMB experience a filtering effect by the endothermic phase change at the 660-km phase transition. Fluid dynamics predicts that the hot mantle plumes stagnate at and locally heat the upper-lower mantle boundary, which causes generation of the secondary plumes in the upper mantle, and hence hotspots volcanic activities on the surface. To understand the effects of heater size on the plumes generation, we have experimentally investigated the behaviors of thermally buoyant plumes generated from a localized heat source (circular plate heater) using quantitative visualization techniques of temperature (TLC) and velocity (PIV) fields. Scaling laws for their ascent velocity and spacing of the plumes are experimentally determined. We also estimate the onset time of the secondary plumes in the upper mantle which depends on local characteristics of the thermal boundary layer developing at the upper-lower mantle boundary.