Abstract
Supercritical geothermal reservoir future geothermal reservoirs are in and around ductile rock bodies. Ductile regime which is estimated beyond brittle zone is target region for future geothermal development due to high enthalpy fluids and relatively weak water-rock interaction. Ductile zone is considered to be developed above 400ºC and below 3 km around active volcanic front in Tohoku District, Japan.