Extraterrestrial Mass Wasting: Comparing Landslides Across the Solar System

Abstract

In this review, mass wasting processes on rocky celestial bodies in our Solar System are investigated. Their occurance is explored on the selected moons, planets, asteroids and comets: the Moon, Mars, Mercury, Ceres, Vesta, comet 67P and comet 9P. A novel classification system is constructed in order to classify mass wasting features in different gravitational and atmospheric environments. The morphology of these mass wasting features is analysed and compared between bodies. Important similarities and differences are discussed and linked to environmental characteristics. The most important factor influencing the morphology is the mobility of the material. In extraterrestrial environments, fluidization of regolith can occur as a result of sublimation of volatiles. Three degrees of fluidization can be distinguished: dry granular flow (no fluidization), lubricated flow (partial fluidication), and sublimation driven flow (fluidized). This fluidization occurs mainly in flow-type movements and can lead to extemely long runout morphologies. A good understanding of mass wasting processes in extraterrestrial environments can provide insights into the surface characteristics of rocky bodies and hint at the presence of volatile substances in the subsurface.