ABSTRACT
Typhoons in 1992 and 1993 in the Chugoku region of Japan induced natural slope failures which caused damage to the transportation and communication networks along the Sanyo Expressway. The damage could be attributed to large-scale falling of trees in the West Chugoku Mountains and to forest denudation which was originally caused by a typhoon in 1991. Accordingly a technical committee was organized by the Chugoku Branch of the Japan Highway Public Corporation to prevent slope the occurrence of further disasters in the region surrounding the expressway. The technical committee investigated the failure of natural slopes around this area using ground surface data together with satellite remote sensing data. This paper examines the reliability of the quantitative analysis technique used to estimate the risk of natural slope failure.
