抄録
The usefullness of the electrical resistivity survey in the Fractured zone type landslide was examiriated at Choja landslide area and Wada landslide area in Kochi prefecture which had many same type landslide. As the result, it was clear that the usefullness of the electrical resistivity survey existed in the Fractured zone type landslide as well as in Tertiary type landslide, and that many informations on the investigated landslide area were pointed out by the electrical resistivity survey.
Thereupon the writer carried out the electrical resistivity survey in order to investigate the usefullness thoroughly, at many other Fractured zone type landslide areas in Kochi prefecture. And the writer tried to examinate the Fractured zone type landslide from the information on the each landslide which was obtained by the electrical resistivity survey.
As the result of this investigation and study, the next informations were gotten:
1. From the assumed diagrams of the underground profile
a. Outline of the underground structure of the landslide area.
b. Fairly exactive informations on the form and depth of slide-surface and bedrock layer.
c. The landslide area could be divided some meaning blocks on account of the landslide area's topographical map which plotted the uncontinuous places of resistivity value seeing the assumed diagrams of underground profile.
d. Even if the bedrock existed so deeply and could not assumed the existed depth of bedrock by the electrical resistivity survey, the shallow slide layer which damaged to the field and houses was detected sufficiently by the electrical resistivity survey.
2. From the analysis of distribution diagrams of low apparent resistivity
a. It was assumed that the distribution area of low apparent resistivity indicated next area: 1. existingarea of aboundant underground water, 2. violent area of landslide displacement, 3. accelerating area of weather of landslide soil mass, 4. possibility existing area which occured landslide displacement in future.
b. In conformity to combine the uncontinuous places of resistivity values which were obtained by the assumed diagrams of underground profile and distribution diagrams of low apparent resistivity, the landslide area was divided same meaning blocks. And in case of making clear the displacement mechanism of the landslide, each divided blocks in the landslide area were having important means.
