Study of morphology and degradation of lunar craters using Chandrayaan–1 data

Abstract

Impact craters are essential and dominant features of the lunar surface. Under the presence of a very thin atmosphere, the degradation of the lunar craters takes place possibly due to gravity, slope processes, or solar wind weathering. Hence, these craters act as tools to understand the properties and processes of the lunar surface. Our analysis is based on the inferences from the craters located in the western hemisphere of the moon. For a long time, the depth to diameter (d/D) ratio and slope of the craters have been used to characterize the craters and to analyze crater degradation processes. However, the d/D ratio and slope are dependent on the size of the crater and therefore cannot be directly generalized for craters of varying sizes. We have thus applied new parameters, namely, slope range and max slope along the wall which along with the d/D ratio and slope can help distinguish the degradation classes of the craters at different ranges of the crater diameter. We have also introduced the topographic roughness index (TRI) near the crater rim which can be used to quantify the roughness of crater rim and to further distinguish the crater degradation classes. Further, our study examines the role of crater shape, i.e., flat-floored or round-floored craters and regional topography on crater degradation. Our study also shows that out of all the round-floored craters in our study area, more craters are in degraded class (class B and class C) than in preserved class (class A).