Geodynamics Research Group

We conduct the research on processes and characteristics of geodynamics and related geological phenomena extend over a long period of time, such as earthquakes, faulting, volcanoes, magma intrusions, uplift, erosion and so on, to evade and/or evaluate the impact of the above geological phenomena. The results will be applied as supporting researches for Nuclear Regulation on performance assessment of natural barrier system of the geological disposal.

Member

Hitoshi Tsukamoto (Leader, Group)

I have been working as engineering geologist and hydrogeologist focusing on hydrogeology and groundwater flow system in granitic rocks for the safety disposal of nuclear waste, but nowadays my current research is to solve the contaminated water issues at the TEPCO's Fukushima Daiichi Nuclear Power Station site and its nearby area based on hydrogeology.

Yasuo Tomishima (Senior Researcher)

In order to perform the performance assessment of a geological repository for high-level radioactive waste and to guarantee the safety, it is necessary to analyze radioactive nuclides migration in geological media which have various delay functions with sufficient accuracy.
In this research, the performance assessment code that based on the one-dimensional random walk method is developed. In order to develop the geological model for a precision performance assessment, calculation of the radioactive nuclide migration in some geological models and accumulation of calculated data are performed.

Makoto Otsubo (Senior Researcher)

I research underground geological characteristics, dynamic geological processes, and the long-term stability of geological environments to understand possibilities of the fault movements, volcanic activity and uplift/erosion. I study constructing long-term dynamic geological modeling for connections between fault and volcanic activities by using the Tectonophysics approaches.

HP: https://staff.aist.go.jp/otsubo-m/index.html

Daisuke Asahina (Researcher)

My research work centers on computational geomechanics. Most of my research has involved using numerical simulations to study mechanical processes and damage evolution of geomaterials. In particular, I am studying initiation and propagation of fractures, as well as transport through permeable media under dynamically changing hydrologic and mechanical conditions. My current research includes validation of coupled models for the geomechanical and hydrogeologic processes associated with disturbances surrounding the excavation for disposal of radioactive waste, which may affect the ability of the repository to isolate waste from the human environment.

Kazumi Ito (Researcher)

 

Sumire Maeda (AIST Postdoctoral Researcher)

 

Manabu Takahashi (Technical Staff)

To quantify the flow-relevant geometric properties of the voids structure under various stress state in rock specimen、the number of connecting path between two faces, coordination number, tortuosity and the shortest path distribution within an arbitrary region are recently investigated using micro focus X-ray CT data.
Previous Works

1. True Triaxial Testing Method : Intermediate principal stress effect on rock strength and deformation characteristics,

2. Seismic Wave Velocity Measurement (P1, P2, P3, SH and SV for the minimum principal stress direction). From these data, we can obtain the geometry of the stress induced microcracks. Crack density, average aspect ratio, crack distribution change with different intermediate principal stress.

3. Quantification of impermeable rock permeability method

4. Permeability evolutions for the intermediate principal stress direction

Li  Yang (Research Assistant)