RINA - Démonstrateur d’utilisation de l’intelligence artificielle pour la gestion opérationnelle des risques naturels gravitaires géologiques | FEREC 2020

by two volcanoes: le Piton des Neiges et la Fournaise. This means that the island resembles two cones with the points being the peaks of the volcanoes. The Piton des Neiges is the oldest and was active 2 million years ago. It created a first lithological structure which is composed of alternating layers of basalt, crystallized magma, and scories, sedimentary rock. Both of those layers have thicknesses below 3 meters. Dykes are also abundantly present on this structure due to volcanic activity. This structure is called the inferieur structure. The volcano became dormant and a stage of erosion started changing the topography of the island. Sediments also started occupying the bed of the valleys that formed a new geological structure. This is called the intermediary structure. About 1 million years ago the Fournaise appeared and a new structure, similar to the first, started to appear. The main difference between both volcanoes is that, as many valleys were present, the magma was more concentrated and early layers reached thicknesses 10 fold more important than the original. This corresponds to the superior structure that covers the majority of the island. With time, a new process of erosion molded the region. As the inferieur structure is older it suffered through more weathering due to the sea and the rain and erosion favored those spaces. All of those steps are illustrated in Figure 6. Figure 3: Map showing the road 9