where dij is the strata dip at cell (i,j); sij is the strata strike at cell (i,j); gij is the slope gradient at cell (i,j); and aij is the slope aspect at cell (i,j).
The landslide susceptibility due to slope relative relief over a given lithology type (lij) is defined in Eq. (8) where rij is the relative relief for location (i,j).