SYSTEMATIC MAPPING AND HAZARD AND RISK CLASSIFICATION OF UNSTABLE ROCK SLOPES WITH A POTENTIAL OF FORMING DISPLACEMENT WAVES IN NORWAY
The hazard analysis is qualitative and includes analyses of the morphological indications of deformation (back scarp, lateral release surface, underlying basal rupture surface), structural analyses and a kinematic feasibility test, as well as analyses of displacement rates, acceleration of displacement rates, rock fall activity, and the analyses of past events. The uncertainty of those observations are expressed with uncertainty margins that result in uncertainty margins of the hazard classification. For each unstable rock slope, a run-out analysis is performed, followed by a displacement wave assessment that shows the area of potential impact of a wave. These analyses are increasing in quality with the risk level.
The risk analysis is focused on loss of life only and is quantitative. We analyze the number of persons that settle in the impact area and those that are transient (e.g. at work, school, in hotels, shops, tourists). As transient persons are also counted, the consequence analysis has uncertainty margins. The final product is a risk classification that is based on a qualitative hazard classes and a quantitative consequence analysis. Relevant data for land-use planning will be published online on http://www.skrednett.no/. Initially, the run-out area and displacement wave run-up area will be published as susceptibility zones. However, a linkage to the quantitative hazard regulation of the Norwegian building code is envisioned.