Development of comprehensive techniques for coastal site characterisation, 1; Strategic overview

Ota, Kunio ; Amano, Kenji  ; Niizato, Tadafumi  ; Alexander, W. R.*; Yamanaka, Yoshiaki*

The assurance of the long-term stability of the geological environment is for deep geological disposal. In Japan, since uplift/subsidence and climatic and sea-level changes would result in a significant change to hydraulic and hydrochemical conditions at coastal sites, it is of importance to establish comprehensive techniques for characterising the overall evolution of coastal sites over geological time. To this end, palaeohydrogeological study is ongoing in the coastal area around Horonobe in northern Hokkaido. A "Geosynthesis Data Flow Diagram" defining a methodology for characterising the palaeohydrogeological evolution of the site has been formulated and, based on the geosynthesis methodology, a basic strategy has been established for stepwise investigations from initial survey of existing information to the final borehole programme at any coastal site. This technique has now been tested and optimised with the progress of the investigations.