The space beneath our feet is gaining in importance. It offers significant potential for spatial planning. Transport routes and infrastructure are now being built underground, and buildings are also increasingly being constructed below the surface. For swisstopo’s National Geological Survey Division, the underground is of great importance because any future use of this space has to be based on reliable fundamental data. Here, 3-D models are a valuable instrument. “They facilitate a continual interpretation of the underground and are thus essential tools for project planning,” says Eva Kurmann-Matzenauer, who is currently developing a detailed 3-D model of the Jura region together with her colleague, Salomè Signer. 

Technology to be further developed

The two geologists are specialising in this working method at swisstopo. They also played a major role in the development of the 3-D model of the Swiss Molasse basin (GeoMol), which covers the central plateau from Geneva to Lake Constance. However, the geological structure of the Jura region is more complex than that of the central plateau, because of the arrangement of the rock layers. Thus the project managers are further developing the 3-D modelling process in the ongoing project.

3-D models are more readily comprehensible than conventional geological maps. “The various rock layers and fractures are clearly visible and recognisable,” explains Eva Kurmann-Matzenauer. Her main area of expertise is structural geology. She is familiar with the spatial circumstances, fractures and shifts beneath the surface. 

Search for suitable solutions

Developing geological 3-D models calls for a high degree of expertise, specialised software and the ability to think three-dimensionally. The two specialists are examining on a step-by-step basis whether developments for a small area of land can also be applied to a larger area. “I find the need to constantly look for new solutions and think outside the box particularly challenging,” says Salomè Signer. The Jura project, which is limited to the region between Sainte Croix and Creux du Van, is currently in its trial stage. 

National maps as basis

A 3-D model is closer to reality if sufficient data are available regarding the region concerned. But the greater the depth to which the modelling process goes, the lower the volume of available data becomes. This means that the scope for interpretation increases proportionally. With the products developed by its National Geological Survey Division, swisstopo is able to provide an ideal point of departure: “We use the maps and profiles depicted in the 1:25,000 Geological Atlas of Switzerland as the main source of data for our studies,” says Salomè Signer. This publication provides detailed information about the underground, and depicts fractures as well as geological links between the rock layers. 

Pioneering work

The two geologists are now working on a concept that will facilitate comprehensive modelling in the future. This means they are carrying out pioneering work. The result will be a basic framework that will also be at the disposal of planning offices, environmental specialists and engineers. “Developing the fundamentals for spatial planning beneath the surface is currently an important activity for the National Geological Survey Division,” explains Eva Kurmann-Matzenauer.

Once the modelling of the central plateau and the Jura region has been completed, the next stage will be to produce a model of the Alps. The 3-D models will pave the way for the intelligent utilisation of the space beneath the surface. They will also facilitate detailed feasibility studies and the balancing of interests. Clearly defined regulations that have to be complied with will also be required for projects below the ground.