Last Update 11/06 2014
Research: The major goal of my study is to understand the interaction between microstructural processes and macroscopic dynamics of partially molten rocks. For this purpose, I experimentally investigate microstructural evolution in a deforming partially molten rock analogue. Also, to connect the experimentally observed microstructural processes to the macroscopic dynamics, I theoretically derive mechanical constitutive relations as functions of microstructural parameters. So far, I found that stress-induced microstructural anisotropy observed in the experiment causes strong viscous anisotropy and then significantly enhances a coupling between matrix shear flow and melt migration. I also investigate the effects of melt on seismic wave velocities and attenuation to derive information on the actual melt distribution in the mantle from seismic tomographic images. Solid state rock anelasticity, which is an alternative cause of low velocity and low Q in the upper mantle, has been poorly understood. So, investigation of anelasticity is also an important subject of my experimental study. Publications: Yasuko Takei and Mineo Kumazawa, Why have the single force and torque been excluded from seismic source models?, Geophys. J. Int., 118, 20--30, 1994. Yasuko Takei, Constitutive mechanical relations of solid-liquid composites in terms of grain-boundary contiguity, J. Geophys. Res., 103, 18183--18203, 1998. Yasuko Takei, Acoustic properties of partially molten media studied on a simple binary system with a controllable dihedral angle., J. Geophys. Res., 105, B7, 16665--16682, 2000. Yasuko Takei, Stress-induced anisotropy of partially molten media inferred fromexperimental deformation of a simple binary system under acoustic monitoring, J. Geophys. Res., 106, B1, 567--588, 2001. Yasuko Takei, Effect of pore geometry on Vp/Vs: From equilibrium geometry to crack, J. Geophys. Res., 107, B2, ECV6-1--ECV6-12, 2002. Yasuko Takei and Ichiko Shimizu, The effects of liquid composition, temperature, and pressure on the equilibrium dihedral angles of binary solid-liquid systems inferred from a lattice-like model., Phys. Earth Planet. Inter., 139, 225--242, 2003. Nakajima, J., Y. Takei, and A. Hasegawa, Quantitative analysis of the inclined low-velocity zone in the mantle wedge of northeastern Japan: A systematic change of melt-filled pore shape with depth and its implications for melt migration, , Earth Planet. Sci. Lett., 234, 59--70, 2005. Yasuko Takei, Deformation-induced grain boundary wetting and its effects on the acoustic and rheological properties of partially moltenrock analogue, J. Geophys. Res., 110, B12203, do, , 2005. Yasuko Takei and Benjamin K. Holtzman, Viscous constitutive relations of solid-liquid composites in terms of grain boundary contiguity: 2. Compositional model for small melt fractions, , J. Geophys. Res., 114, B06206, doi:10.1029/2008JB005851, , 2009. Yasuko Takei and Benjamin K. Holtzman, , Viscous constitutive relations of solid-liquid composites in terms of grain boundary contiguity: 3. Causes and consequences of viscous anisotropy, , J. Geophys. Res., 114, B06206, doi:10.1029/2008JB005852, , 2009. Yasuko Takei and Benjamin K. Holtzman, Viscous constitutive relations of solid-liquid composites in terms of grain boundary contiguity: 1. Grain boundary diffusion control model, J. Geophys. Res., 114, B06206, doi:10.1029/2008JB005850, , 2009. Yasuko Takei, Stress-induced anisotropy of partially molten rock analogue deformed under quasi-static loading test , J. Geophys. Res. , 115, B03204, doi:10.1029/2009JB006568, , 2010. Takei, Yasuko; Fujisawa, Kazuhiro; McCarthy, Christine, Experimental study of attenuation and dispersion over a broad frequency range: 1. The apparatus, J. Geophys. Res., 116, B09, B09204, doi:10.1029/2011JB008382, , 2011. McCarthy, Christine, Takei, Yasuko, Hiraga Takehiko, Experimental study of attenuation and dispersion over a broad frequency range: 2. The universal scaling of polycrystalline materials , J. Geophys. Res., 116, B09207, doi:10.1029/2011JB008384 , , 2011. McCarthy, Christine; Takei, Yasuko, Anelasticity and viscosity of partially molten rock analogue: Toward seismic detection of small quantities of melt, Geophys. Res. Lett., 38, L18306, doi:10.1029/2011GL048776., , 2011. Yasuko Takei and Richard Katz , Consequences of viscous anisotropy in a deforming, two-phase aggregate. Part 1. Governing equations and linearized analysis, Journal of Fluid Mechanics , 734, November, 424--455, 2013. Richard Katz and Yasuko Takei, Consequences of viscous anisotropy in a deforming, two-phase aggregate. Part 2. Numerical solutions of the full equations, Journal of Fluid Mechanics , 734, November, 456--485, 2013. Yasuko Takei, Fumiya Karasawa, Hatsuki Yamauchi, Temperature, grain size, and chemical controls on polycrystal anelasticity over a broad frequency range extending into the seismic range, J. Geophys. Res., 119, doi:10.1002/2014JB011146, , 2014. |
