Combining geomorphological, historical and lichenometrical data for assessment of risk due to present-day slope processes, a case study from the Icelandic Westfjords

Present-day slope processes are the cause of large damage in fjord areas of Iceland. Among all active slope processes, this paper focuses on snow-avalanche and debris-flow impacts in four places located in the north-western part of the island. Spatial distribution of slope processes close to inhabited areas is obtained from geomorphological investigations while dating data are given with the help of historical records and lichenometrical analysis. The combination of the information reveals spatial and temporal patterns of snow avalanches and debris flows in the studied areas. By so doing, slope process runout distances are compared with inhabited spatial extension, which clearly underlines the risk apparition and then its exacerbation during the last century by an increasing superimposition of both phenomenons.