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

Based on the calculated points a manual line was traced in order to have more spatially continuous points and therefore, more continuous values should be expected for the indices calculated for the topographic and hydrological description. The final points used still had some discontinuities, but less of them and, moreover, there aren’t outliers as seen in the image above (Figure 16). With those points, the equations shown on Figure 13 are applied and Figure 17 can be produced. As noted previously, both values seem mirrored, higher values of Standardized area leads to smaller values of SCI. Figure 17 : Variation of the topographic indices along the road. The fifth and last value calculated to describe the cliff was the Topographic Wetness Index (TWI). It is calculated with the topographic map and indicates the concentration of water of a point according to the direction of runoff. Q-GIS was used to calculate the value for every 10 m square inside the watershed []. In order to have one value for the different points it was decided to use the value for the point from which blocs depart as generally cumulated waters behind the cliff infiltrates and causes pressures that cause blocs to detach. The final result can be seen in Figure 18. 24