ABSTRACT
The fractures play important roles for the transport of liquid and vapour. Many fractures have taken place in the Green Tuff region along the Japan Sea side of the Japanese islands since early Miocene, where many Quaternary volcanoes are distributed. Yakumo geothermal field is studied, which is located in the northern part of the Oshima Peninsula, southwest Hokkaido, Japan. The most important parameter for Virtual Basement Displacement (VBD) method is the surface deformation resulting from the movement of the basement, and the displacement on the surface is assumed to approximate the thickness of the formation during the stage. The VBD vector is given as vertical and horizontal displacement vector components. The experiment of the VBD method gives the distribution of incremental deformation, strain, principal stresses, fractures and cumulative deformations at each stage.
