Geotypen : ein neues Konzept zur Optimierung geologischer Informationen für die Raumplanung

When we have to valorise the geological information for land planning or engineering applications, it is difficult to integrate the large complexity of the maps of the Swiss Geological Atlas at the scale of 1:25'000. The heterogeneity of the legends between neighbouring maps is often another difficulty. That is the reason why we proposed the notion of «geo type», a concept that describes in a simplified and homogeneous manner the principal geological formations at the scale of a canton. The experience in the Canton de Vaud demonstrates that the use of geotypes allows a translation of the geological information of maps and boreholes in terms of properties that are useful for applied geology. Each geotype is characterized by a table of properties like, for example, an order of magnitude of thermal conductivity, permeability, grain size distribution, plasticity etc. This characterization proved its robustness in different domains like seismic microzoning, groundwater resources, geothermy and slope stability. A recent application is the DEEP CITY project which characterizes the underground resources below the cities where 3D models in geotypes are established. The numerical modelling operations are easier to be performed. The geo types do not replace the academic geological information, which remains the base, particularly the geological maps of the Swiss Atlas.