... pits and faults.
In the lower right portion of the image, a 35 km impact crater gives interesting insights into the subsurface. Here, an approximately 20 km long, 9 km wide and several hundreds of meters deep pit opens and exposes different alternating layers in the subsurface. Some of the layers appear to be composed of brecciated materials. The curvilinear form of a prominent fault inside the pit suggests a formation by collapse. This kind of collapses are known to happen in volcanically active regions where ancient lava tubes or magma chambers emptied and as a consequence created voids in the underground which later collapsed. The region in and around Mare Serpentis is known to have been volcanically active in the past.