Controls on the Global Distribution of Martian Landsliding

Abstract

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 (Crosta et al., 2018a, b) inventory of Martian landslides, 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. We analyzed for but did not find a clear local lithologic or stratigraphic control on landslide occurrence from subsurface heterogeneities. Other possibilities to explain the increased occurrence of landslides in the Tharsis Rise include (1) regionally widespread Tharsis weak unit(s), such as from interbedded ashes and lavas; (2) seismic activity related to the Tharsis Rise’s geological activity, and (3) possible groundwater near Valles Marineris into the Amazonian. Given the apparently young ages of many landslide deposits in Valles Marineris (Quantin et al., 2004), continued modern day analysis of lithologies in Valles Marineris and observations of Martian seismicity may act to strengthen or rebut the first two hypotheses.