Development of methodology for quantitative landslide risk assessment—Example Göta river valley

Abstract

Effective landslide risk management requires knowledge of the landslide risks. This paper presents a risk assessment methodology for semi-regional scale. The landslide probability is assessed taking into account expected climate-change in the case study area (the Göta river valley). Climate change is expected to result in increased erosion and water fluctuations. There are large areas with marine clays, often quick clay, in the area and the landslide process can be rapid with extensive damages and casualties. The consequence methodology includes a wide range of consequences assessed by monetary valuation. The consequences and the landslide probability are combined as pairs of values in a risk matrix and the risk is also presented on a map. The map has been used as discussion and decision bases in the municipalities in the Göta river valley, in the county administration and on governmental level to estimate the needs of risk mitigation and to make priorities.