Research Interests

[Research topics]

An origin of macroscopic friction

H. Sakuma, K. Kawai, K. Katayama and S. Suehara,

Science Advances, 2018

Can we explain macroscopic friction from the atomic-scale friction? We have tackled to understand the relationship between macroscopic and atomic-scale friction of mica. Mica is one of clay minerals which are ubiquitous in natural faults. The results of shear experiments of single-crystal mica (muscovite) was quantitatively explained by the atomic-scale friction simulated by the density functional theory (DFT) calculations. The atomic-scale roughness generated by the electron-electron interactions is a major origin of the macroscopic friction. 

[Research topics]

Electrical conductivity of NaCl-H2O fluid in the crust

H. Sakuma and M. Ichiki,

Journal of Geophysical Research: Solid Earth, 2016

Presence of aqueous fluids in the Earth’s crust is essential for earthquake occurrence. The distribution of the fluids in the crust has been investigated by measuring the electrical conductivity based on a hypothesis that the conductivity of aqueous fluids should be higher than rocks and minerals in the crust. The electrical conductivity of aqueous fluids is, however, unknown at elevated temperature and pressure. We revealed the electrical conductivity of NaCl-H2O fluids in the crustal conditions by using classical molecular dynamics simulations. Our data can be used for estimating the salinity and volume fraction of NaCl-H2O fluids in the crust.

[Research topics]

Frictional characteristics of single and polycrystalline muscovite and influence of fluid chemsitry

K. Kawai, H. Sakuma, I. Katayama, K. Tamura,

Journal of Geophysical Research: Solid Earth, 2015

Frictional properties of mica and clay minerals are critical on the sliding behavior of natural faults. We investigated the frictional properties of single and polycrystalline muscovite for understanding the low friction coefficients of these layered minerals. 

Physical chemistry of mineral/water/organic molecules interfaces

the effect on

Creeping Faults

Supercritical phase

Migration of Toxic Species

Electrical Conductivity of Aqeous Fluids

Self-organization of Organic Molecules on Mineral Surfaces

Water in minerals

Enhancing Oil Recovery

Nanocomposite.