In this region, are many expanded secondary craters that probably form from impacts that destabilize a subsurface layer of excess ice, which subsequently sublimates.
In the impact, the excess ice is broken up, resulting in an increase in surface area.
After the ice disappears into the atmosphere, dry soil material will collapse and cause the crater diameter to become larger.
[2] Based on measurements and models, the researchers calculated that at least 6000 Km3 of ice is still preserved in non-cratered portions of Arcadia Planitia.
[5][6] Places on Mars that display expanded craters may indicate where future colonists can find water ice.