Collapse Features near Alba Patera (Enhanced and Saturated Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)

Caption NASA:"Alba Patera is a very large old volcano on the surface of Mars. While still impressive in height, it no longer towers over the surrounding plains.
It is thought that after a major eruption that emptied the magma chamber beneath Alba Patera the entire volcano collapsed into the empty space below.
This collapse is marked by extensive fracturing. This VIS image shows collapse features on a much smaller scale".