Investigating Mars: Ascraeus Mons

This image shows part of the southern flank of Ascraeus Mons. The feature at the bottom of the image is a collapse feature. These features can be caused by several processes. The ceiling of lava tubes can collapse into the open space left after the last flow. Tectonic activity can occur, and blocks of material can drop down between faults. The tectonic features are called graben. All three of the Tharsis volcanoes (Ascraeus, Pavonis and Arsia mons) are aligned along a northeast/southwest trend.