THEMIS Image of the Day, July 10, 2018. 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.
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