Thermal inertia variations from gully and mass-wasting activity in Gasa crater, Mars

Abstract Gasa crater has been the most active site observed on Mars to date, making it of particular interest for studying the process(es) behind gully formation and activity. In this study, we investigate whether differences in thermal inertia across different segments of gully systems, combined with morphological and colour observations with High-Resolution Imaging Science Experiment (HiRISE), can provide some constraints on the physical characteristics associated with recent activity within gullies in Gasa. We also investigate thermophysical differences between slopes in Gasa dominated by gully activity compared to those predominantly modified by dry mass-wasting processes. We find that Gasa crater exhibits clear variations in thermal inertia across its walls, controlled by the material properties and the types of dominant mass movement processes occurring on each wall. The youthful gully-fan lobes display thermal inertia values c. 20–40 J m −2 K −1 s −1/2 higher than adjacent older eroded and dust-covered lobes. The talus aprons from mass wasting in Gasa have thermal inertia values c. 60–80 J m −2 K −1 s −1/2 higher than gully aprons. The results of this study thus suggest that thermal imaging can inform us on surface change detection on Mars.