Japan Geoscience Union Meeting 2015

Presentation information

Oral

Symbol S (Solid Earth Sciences) » S-VC Volcanology

[S-VC46] Dynamics of volcanic eruptions and igneous activities

Mon. May 25, 2015 11:00 AM - 12:45 PM 304 (3F)

Convener:*Tomofumi Kozono(Department of Geophysics, Graduate School of Science, Tohoku University), Yujiro Suzuki(Earthquake Research Institute, The University of Tokyo), Satoshi Okumura(Division of Earth and Planetary Materials Science, Department of Earth Science, Graduate School of Science, Tohoku University), Chair:Tomofumi Kozono(Department of Geophysics, Graduate School of Science, Tohoku University)

11:00 AM - 11:25 AM

[SVC46-14] Stokes--DEM coupled simulation for a granular media of magma chamber

*Mikito FURUICHI1, Daisuke NISHIURA1 (1.Department of Mathematical Science and Advanced Technology, Japan Agency for Marine-Earth Science an)

The dynamics of a granular media has been suggested to play an important role in a reheated magma chamber by a hot intrusion (e.g. Burgisser and Bergantz, 2011). Although several mechanisms, such as Rayleigh Taylor instability, unzipping, and rhythmic convection (e.g. Shibano et.al. 2012, 2013) have been proposed for characterizing an evolution of crystalline magma chamber, their contributions in the long geodynamical time scale are not clear yet. Thus we performed dynamical numerical simulations of the granular material in three dimensions to investigate the thermal evolution of the magma chamber.
In order to solve high-viscosity fluid and particle dynamics for modelling a melt--crystal jammed state of the magma, we have developed a coupled Stokes--DEM simulation code with two key techniques: formulation of particle motion without inertia and semi-implicit treatment of particle motion in the fluid equation (Furuichi and Nishiura, G-cubed, 2014). Our simulation can successfully handle sinking particles in a high-viscosity fluid.
In our simulation, the top fluid--particle jammed layer is heated by the hot basal fluid at the bottom. This initial setting represents the first-stage toy model for an erosion process at a melting roof of the magma chamber. We have investigated the dynamical patterns of the settling particles which strongly depend on the rheology of the granular layer. In addition, we have also examined the dynamical role of the density of the basal hot melt. Our numerical result indicates the possibility of the spontaneous formulation of crystal rich layer on the basal dense melt layer.