Landslide risk assessment and acceptable risk

Definitions for risk and hazard which are suited to landslide risk assessment are presented. Acceptable risk is discussed in relation to other risks accepted by the community, and acceptable specific risks are proposed, depending on whether the landsliding is natural or sliding of a man-made slope. Methods for quantifying the risk are discussed, and qualitative definitions are suggested for use when these are desirable. Examples are given of use of risk assessment in areas affected by landsliding and debris flows. Key words : landsliding, slope stability, risk assessment.