Natural-Hazard Maps for Land-Use Planning in Norway

Problems concerning natural-hazard mapping have been discussed by the Norges Geotekniske Institutt in pilot projects sponsored by the National Fund for Natural Disaster Assistance. Hazard-registration maps, geomorphic hazard maps and hazard-zoning maps are defined. Hazard-zoning maps are preferable in land-use planning. Both survey maps (1 : 50000) and detailed maps (1:5000) are of interest. A survey map (c. 600 km2) would be mainly based on airphoto interpretation and could be prepared in about 150 h. Detailed mapping is more time consuming and should be limited to development areas. Mapping of “marine deposits” and “other areas” are handled by separate groups, mainly because of differences in technical and professional problems. This gives rise to two parallel series of survey maps and detailed maps. The proposed programmes for survey mapping states that 80% of the marine areas should be evaluated in 5 years (1980-84), and that one-third of the country should be examined for rockfalls, rock slides, and snow avalanches in 10 years. Other hazard types are impossible to identify by survey mapping. There is a rising demand for detailed maps but as yet there has been no research project to standardize methods. The hazard maps are intended primarily to be an aid in land-use planning.