Technique for underground survey on thrust fault zone

Kagohara, Kyoko; Kurosawa, Hideki; Ishimaru, Tsuneari ; Nohara, Tsuyoshi   

Assessment of the effects of earthquakes and faulting on the deep geological environment is absolutely essential for site selection and design of high-level radioactive waste repositories in Japan. For thrust faults, there are widely deformations in strata or surface, complex geological structure caused by blind thrust, and lateral propagation and growth. Thus, it is important to understand the morphic character and history of thrust faults, based on the tectonic landforms and underground structures. Here, we presented the results of the case study at the Yokote basin fault zone that is a typical thrust fault of Japan. It reports on the relation between geographical features and underground structure of the Yokote basin fault zone.