Crustal Fluid Research Group

We conduct the research on processes and characteristics of groundwater systems based on volcanology, geochemistry and hydrology to evaluate: 1) residence time of groundwater flow system, 2) circulation rate and origin of fluids in the earth's crust, 3) magmatic volatile or slab-derived fluid flux to groundwater systems. The results will be applied as supporting researches for Nuclear Regulation on performance assessment of natural barrier system of the geological disposal.

To group homepage (in Japanese)


Noritoshi Morikawa (Leader, Group)

I am studying about the origin and residence time of deep groundwater using noble gas isotopes including helium. My research filed is now extended to the investigation of the age and recharge condition for shallower groundwater using tritium-3He method and atmospheric noble gas concentration (Noble Gas Hydro-Geochemistry).

Toru Shimizu (Senior Researcher)

I have been specialized in ore mineralogy and geology. Up to date I have focused hydrothermal metallic deposits (Hishikari, Toyoha and Koryu), in terms of ore petrography, fluid inclusion microthermometry and stable isotopes analysis. Hereafter, I will mainly engage in a fluid inclusion research on the hydrothermal minerals to understand the deep fluid convection system in Japanese island arc.

Hiroshi Takahashi (Senior Researcher)

The investigation about carbon species in groundwater is conducted inferred from the stable and radioactive carbon isotopes. Especially, radiocarbon groundwater age and the estimations of deep-seated carbon in groundwater and ascending geogenic fluid are focused in the present works.

Yoko Togo (Senior Researcher)

I have been working on iodine speciation and determination of 129I/127I ratio in groundwater and its host rocks to understand the behavior of iodine in environments. My current research is to determine the distribution of iodine in groundwater in Japan. I also investigate the paleoenvironment of deep underground based on the chemical compositions of groundwater and its rocks collected from the underground research laboratories in Mizunami and Horonobe (Japan Atomic Energy Agency).

Hitomi Nakamura (Senior Researcher)


Kohei Kazahaya (Invited Senior Researcher)

I have been working as volcanologist, geochemist and hydrologist focusing on: 1) degassing and diffusive mechanism of magmatic gases to the atmosphere and groundwater system for long-term prediction of volcanic activities based on monitoring of volcanic gas flux and groundwater surveys, and 2) quantitative estimate of slab-derived fluid contribution and flux to groundwater systems using isotopic and chemical tracers for the assessment of long-term groundwater stability on the safety disposal of nuclear waste.


Masaaki Tahkahashi (Technical Staff)

I am studying about 1) the origin and formation mechanisms of brine and the relationship with mud volcanism, geochemically, 2) accurate and quick hydrogen and oxygen isotopic analysis of subsurface water with mass spectrometry and cavity ring down method (laser spectrometry), and 3) geochemical data compilation for the database of deep groundwater chemistry. I surveyed in geothermal fields in Indonesia (Flores and Sumatra islands), the Izu Islands (Izu Oshima and Aogashima islands), etc.