Observing Lunar Rilles, Rupes, and Vallis

Abstract

Some areas of the Moon’s surface are crisscrossed by kilometers-long linear depression features; “cracks” as Wilkins and others called them. Many of these features do appear to be simply cracks, but their true nature is more complex than that. The classification of these linear features depends primarily on their particular creative processes. The shallow fault trace or meandering river-like features are all called rilles. The generally deeper and wider linear depressions are known as either a catena (crater chain) or a vallis (valley). In this chapter we will observe these linear features and cover the different endogenic and external processes by which they were formed.