Seminar by Giulia Magnarini (LPG, Osuna, Marie Curie fellow) – “Long-runout landslides with longitudinal ridges in the solar system: what controls their formation?”

Long-runout landslides are amongst the most catastrophic type of mass movements, and yet one of the least understood. Much work has already been done to study the behaviour of these landslides, yet the origin of their hypermobility is poorly understood. One key morphological feature that is ubiquitously documented in long-runout landslides are distinctive longitudinal ridges. However, the relationship between the emplacement of long-runout landslides and the development of their longitudinal ridges remains undefined. To date, landslides with longitudinal ridges have been documented across the Solar System, including on Earth, the Moon, Mars, Ceres, Iapetus, and Rhea.

On Earth, at the present day, long-runout landslides with longitudinal ridges are only seen developing over glaciers in remote mountain areas, and so they are often associated with the presence of basal ice. Their morphological similarity with martian landslides has been used to suggest the past presence of ice on Mars. Understanding the origin of these landforms and their possible link to past environmental conditions is important to reconstruct the climatic and surface evolution of rocky planetary bodies. On Earth, this geomorphological record is critical to understanding where, when, and how these catastrophic events occurred, thus critical to addressing a key question in hazard assessment: how likely events of similar magnitude to those of the past are likely to occur in the future?

In this presentation, I will discuss the work that I have done on long-runout landslides with longitudinal ridges on Mars, Earth, and the Moon, including the only extraterrestrial landslides that have been studied in-situ by Apollo 17 astronauts. I will also present the work that I have been conducting in Iceland as part of my Marie Curie Fellowship at LPG, and on Mercury as Guest Investigator for BepiColombo.