Hazard and risk assessment of landslides

The evaluation of the safety of natural or man-made slopes involves uncertainties. With a deterministic safety factor, the geotechnical engineer tries to deal with the uncertainties by choosing reasonably conservative parameters for stability evaluation. The deterministic approach fails to deal consistently with uncertainties. As a complement to the deterministic approach, a probabilistic approach that allows for hazard and risk assessment of slopes is recommended. The paper proposes a framework integrating existing methods to exploit the benefits of the two approaches. Societal aspects, including allowable and tolerable risk, are briefly considered. The need for input on the social dimension of landslides, and the role of risk assessment in easing communication among the different experts are also discussed.