Impacts of the increased rain due to climate change on shallow landslides and sediment runoffs in Kyushu District, Japan

Rainfall observation by pluviometer for 30 years up to 2008 and sediment discharge monitoring (periodical observation) over 4 years with sediment trap facilities were conducted in Fukuoka (Northern Kyushu). On the other hand, rain-sediment discharge observation for 30 years up to 2006 at hydroelectric power dams and shallow landslide analysis using aerial photographs for typical 3 years were conducted in Miyazaki (Southern Kyushu). Both of these areas are characterized with severe landslide events. Geologically, research areas consist of Paleozoic and Mesozoic rocks (mainly schist, Phyllite, sand stone), whereas vegetation is composed mainly of Japanese cypress and cedar. Theoretical analysis with physical equation and statistic analysis with Kendall’s rank correlation are conducted with the data obtained in these areas. Consequently, following results were obtained.