Seen here is a geological "fault" on the Moon, called Rupes Recta, as seen from orbit by NASA's Apollo 16.
A fault like this is called a scarp when it separates two relatively level areas. Scarps are formed when two volumes of rock are displaced from each other due to stressing of the lunar crust and interior. The scarp of Rupes Recta stretches for 110 kilometers long and its wall is about 240 to 300 meters high.
Rupes recta is a popular spot to observe for amateur astronomers. Similar to graben, studying and sampling material of the sides of the scarp will tell us about the evolution lunar crust.