Slipping And Sliding In Echus Chaos On Mars
Echus Chaos is a region of low hills located between Lunae Planum (to the right of this image) and Echus Palus (to the left of this image).
This chaos terrain may have formed as the rocks that make up Lunae Planum slowly slid downhill into Echus Palus. As these rocks slid downhill, they broke up into large pieces that formed the hills that we see today.
What caused this landslide is not well known, but it could have been due to large floods of water moving through Echus Palus, causing the edge of Lunae Planum to become soaked and fall apart. Ground shaking from movement along nearby faults or meteorite impacts may have also helped to make the edge of Lunae Planum unstable and collapse.
NASA ID: PIA25556
https://photojournal.jpl.nasa.gov/catalog/PIA25556