This VIS image is located on the eastern flank of Alba Mons. Linear faults and graben surround the volcano aligned north/south, intersecting and deflected around the summit. The large graben is called Phlegethon Catena. The term catena means a string of craters or circular depressions. The depressions in this image were likely formed by the collapse of the preexisting surface into a subsurface void. Graben are caused by blocks of material that drop down along paired faults.
Orbit Number: 72405 Latitude: 36.2522 Longitude: 255.129 Instrument: VIS Captured: 2018-04-11 00:39
https://photojournal.jpl.nasa.gov/catalog/PIA22596