Effondrement d’un pavillon, sur la commune de Saint-Pryvé Saint-Mesmin, le 22 mai 2010. Fontis de 9 m de profondeur lié à un karst (Loiret, 2010).
Building in safe places is not always straightforward. In the mountains, we should watch out for falling stones. Along the coast or near a river, we need to beware of floods. Earthquakes and volcanoes are a threat in other areas.
In the Orléans region, we must look at what lies under our feet. Over time, the karst-forming bedrock has been altered by water and is now full of cavities. Fortunately, there are not too many holes in this Swiss cheese. And by taking a few precautions and relying on local memories, problems can be avoided or at least reduced.
This presentation will first provide a geological description of the region. It will then show why the region’s geomorphology presents geohazards, while also providing resources. Lastly, the presentation will cover various methods for managing risks and conserving these resources.
This lecture draws on the knowledge gained from the PERCIVAL research project co-financed by the Centre-Val de Loire region, and led by BRGM and the University of Tours CITERES laboratory, in collaboration with other partners.
Gildas Noury is a geological engineer at BRGM. He specialises in geotechnics and is currently working on geohazards associated with subterranean cavities, with a particular focus on karst processes occurring in the Orléans valley. His research benefits from close collaboration with many colleagues specialising in fields such as geology, karstology, cavity mapping, hydrogeology, geophysics, natural hazards, and socioeconomics of risks.
Free online lecture