Mapping an urban area prone to slope instability: Greater Lyons

摘要

In response to the needs of the local authorities, the systematic mapping of zones prone to slope instability was undertaken for the urban area of Lyons, the second largest city of France with a population of 1.2 million. This involved working within operational constraints, including the extent of the study sector (some 300 km~2 of the 500 km~2 covered by the urban area), an accuracy of 1:5,000 scale throughout, difficulties of ground observation in an urban environment and a limited budget. An original methodology was developed and implemented to deal with these constraints. This combined automatic mapping methods using GIS (cross-checking slope and geological criteria) with naturalistic assessment methods (visual analysis). The results obtained met the expectations of the local authorities. After checking, the maps produced were appended to the regulatory urban planning documents under development.