LAUSR

Landslides have been observed in different terrestrial environments and also on planets, satellites, and asteroids. Long runout landslides are strongly dependent on the initial mass position, material and slope path properties, topographic relief, and presence of volatiles. Therefore, landslides represent a means for the description of rock properties and environment of deposition prevailing at the time of occurrence and may assist in understanding the geological and climatological history of the planetary surfaces. Concerning Mars, previous studies have concentrated on Valles Marineris, where among the largest and longest landslides have been observed. Using different imagery, we present and analyze an original database of 3,118 Martian landslides of deposit area greater than 0.1 km throughout the planet between 60°N and 60°S, resulting in a data set far richer than previously done. After a distinction is made between different typologies of landslides, their position and the statistical distribution of their geometrical properties are examined. Large landslides cluster along the Noctis Labyrinthus-Valles Marineris-Margaritifer Terra system. Rock avalanches within craters are widespread, but no significant large landslides have been found at latitudes higher than 40°S and 46°N. The magnitude-frequency distribution follows a power law with scaling exponent ranging between 1.02 and 1.57, for the entire data set and varies according to the geomorphological settings, the landslide typology, and mobility. A volume-area power law relationship (exponent: 1.12–1.24) is proposed, based on the reconstruction of 222 landslide geometries, and compared to those for similar terrestrial landslides (1.39). Similarities with respect to terrestrial landslide, distribution with respect to impact craters and impact energy, and cryosphere extent are also discussed. Plain Language Summary Landslides are geomorphological phenomena that can strongly control the evolution of a landscape. They have been observed in different environments on planets, satellites, and asteroids. Landslides are sensitive to rock strength, slope geometry, and geological and environmental conditions and to their perturbations. Long runout landslides are characterized by exceptional runout and are dependent on the material and slope path properties, path geometry, presence of ice, water, liquefied soil, and vapor. Therefore, they can spread light over the conditions existing at a specific site or region or even a planet. Martian landslides are the best preserved in the whole solar system. We present and analyze an original database of about 3,100 Martian landslides spread throughout the whole planet. We study the position of landslide types and the statistical distribution of their geometrical properties, from which details of the rock material and the possible triggering and landslide dynamics can be inferred. Rock avalanches within craters are widespread in the planet, but no significant large landslides have been found at latitudes higher than 40°S and 46°N. Similarities with respect to terrestrial landslides, distribution with respect to impact craters and impact energy, and cryosphere extent are also discussed.