Abstract
Case study using base friction model and DEM of Echizen rock fall disaster in Fukui prefecture in 1989 indicates that a risk analysis by disaster scenario and risk assessment matrix is useful decision-making tools for reduction of rock fall disasters which have many uncertainties in their occurrence and consequence. The matrix consists of both axes i.e. likelihood of event occurrence and impact of consequence, and normally the matrices should lead to decisions in three categories or priorities.
In order to propose more probable scenarios we should prepare and apply useful data-base of rock fall disaster inventories.
