As part of the thesis of Fils Vainqueur BYIRONGIRO (thesis CNRS Prime 80), Marc, Fils Vainqueur and Olivier study on the ground the causes of landslides in Rwanda and their impacts on socio-economic developments. Rwanda is the country with the highest population density and the many landslides are a significant risk causing many deaths. Better understanding of triggers will enable local decision makers and put in place a better prevention strategy