The site of Higashidori nuclear power station is underlain by Neogene Miocene consisting of pyroclastic and sedimentary rocks. Marine terrace deposits of upper Pleistocene overlays these formations. In those Miocene the major normal faults are observed, which fracture zones have partly undergone hydrothermal alteration, mineralization and lithification during Neogene period. These features indicate that those faults are not active at least in the late Quaternary. On the other hand, in the Quaternary sediments that covers the weathered rock or the fault, “deformation“ such as fault gouge injection into the sediments, upward convex form and so on. Based on enormous surveys, those are caused by volume expansion or heaving of rock deteriorated parts.