LANDSLIDES ON ICY PLANETARY SURFACES (Invited Presentation)

With technological advancement, we observed and map the icy planetary surfaces under high resolution which were previously seen under earth-based telescopes. These icy planets are proposed to be active until recently due to various geological processes [1]. One commonly observed process on extraterrestrial bodies is landslides, also known as ‘mass movement’ where the downward movement of dust, rock, debris, and other organic material is observed [2]. Therefore, in this study, we compare and summarize our landslide observations of Vesta, Ceres, Europa, and Callisto to understand the influence of volatile distribution on landslide initiation and mobility. On Vesta and Europa, the most commonly observed mass wasting process is sliding which shows features such as spur/gully-like morphology, apparent albedo variation, brittle boulders within deposit margins, and thick bedrock chute. A large number of observed sliding features on Vesta suggests dry granular regolith due to its low volatile concertation [3 whereas, similar sliding features indicate frost-rich granular regolith on Europa. In contrast, the majority of noted mass wasting process shows flow-like movement on Ceres and Callisto which shows characteristics such as a thick lobate bulge in the direction of movement, large alcove fan-like deposit morphology, striations of brittle material during the mobility [4, 5]. On both planetary bodies, this type of mass deposit travels a relatively longer distance due to higher momentum. The morphology of icy planetary bodies and surface degradation processes such as mass movement combines the nature of extraterrestrial environments with surrounding geology, many of which are commonly observed on Earth. Overall, landslide features have the ability to expose fresh regolith material and reveal the possible existence of subsurface volatiles which may have played a vital role not only as a triggering mechanism but also during the evolution of the icy planetary surface.

References: [1] Singer et al., 2012, Nature Geoscience, 5(8), 574–578. [2] De Blasio, 2011,Springer Science & Business Media. [3] Jaumann et al., 2012, Science, 336(6082), 687–690. [4] Parekh et al., 2021a, JGR: Planets, e2020JE006573. [5] Chuang et al., 2000, JGR: Planets, 105.E8 (2000): 20227-20244.