CONTROLS ON THE GLOBAL DISTRIBUTION OF MARTIAN LANDSLIDING

Recent acquisition of high-resolution satellite imagery of the Martian surface has permitted landsliding to be studied on a global scale on Mars for the first time. We apply the Scoops3D software package to compute slope stability for select regions of the Martian surface, combining calculations of slope stability with number of observed landslides, as reported in a recently published inventory of Martian landslides (Crosta et al., 2018a, b) to understand controls on the global distribution of landsliding on Mars. We find that the distribution of landsliding does not simply follow the distribution of unstable slopes. In particular, there is an increase in landsliding in the Tharsis Rise area, and especially in Valles Marineris and Noctis Labyrinthus, that is not explained by an abundance of unstable topography alone. While patterns of mapped landsliding do not follow patterns of mapped faulting across most of Mars, there is an increase in landsliding near mapped faults in unstable terrain in Valles Marineris. Lithology does not appear to be a strong control on landslide abundance in the Tharsis region, although relatively young outcrops of aqueous minerals suggest that atypical regional groundwater late into Mars’s history could also have influenced landsliding in the vicinity of Tharsis. In general, while patterns of Martian landslide distribution are strongly correlated with topography, spatial variation in non-topographic factors is needed to fully explain the distribution of landsliding. Evidence for spatially variable Martian seismicity from the InSight lander could help clarify the importance of one of these factors.