AS 15-0018 - On the rim of Gibbs Crater

Impact craters with asymmetric ray patterns and profiles can be caused by conditions other than the angle of trajectory. This 5-Km crater was formed when a meteoroid impacted on the North-East rim crest of Gibbs, a very much larger and older crater near the Moon's East limb. In this restricted view, Gibbs' rim is the dark area in the North half of the picture, and its wall is the light area in the south half. The rim crest extends from arrow to arrow. Discrete rays of both light and dark ejecta are well developed around the North half of the small crater where they were deposited on a relatively level surface. They are poorly developed around the South side of the small crater, probably having been partly destroyed by mixing as the ejected materials cascaded down the much steeper wall of the Crater Gibbs. Subsequent erosion has further destroyed the original pattern. The configuration of the small crater's rim has also been affected by topography.
It is sharply defined along the North side but is barely discernible along the south side where large volumes of material have slumped down the wall of the older crater.