Steep interior wall of Kepler, the crater's northwest rim is to the upper left and interior toward the lower right. Note the exposed layering near the top and boulders collecting at the base of the crater wall. From LROC Narrow Angle Camera observation M107128381R, LRO orbit 926, September 9, 2009; field of view is ~ 800 meters [NASA/GSFC/Arizona State University].
LROC News System
Landslides are primarily caused by gravity pulling loose material down a slope. Numerous factors contribute to landslides on Earth, including water and vegetation, but these can be ignored for the Moon. However, both bodies are affected by the angle of repose which is related to the cohesiveness of the material making up the slope. Once the angle of repose is exceeded the loose material on the slope slides downhill. Since the exposed bedrock layer near the top of the wall is more cohesive it stays intact while loose rocks and dust slide from underneath. As the wall material continues to slide down, more of the resistant layer will be exposed until it is undermined and is pulled down by gravity. The boulders at the base of the landslides are probably pieces of the bedrock layer.
The range of two LROC NAC observations from early November 2010, from which consecutive Featured Images were derived are seen draped over the Google Earth lunar digital elevation model of Kepler's interior, once again suggesting the vast improvements in resolution since the base albedo map from the Clementine (1994) mission was gathered [NASA/GSFC/Arizona State University].
Explore the rest of Kepler's rim in the NAC image!
Kepler Crater Ejecta