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Brooksee83 t1_j96m2ci wrote

Reply to comment by Present_Reason2097 in This image of Mars shows the north polar ice cap, the border between highlands and lowlands, former river valleys, plains covered by dark sands and the large Hellas Planitia impact basin in the south. Credit: ESA/DLR/FU Berlin by MistWeaver80

Think of the surface as a pool of liquid and imagine a water drop landing in the pool. You typically see the middle pop back up after the original crater shape has fallen in. Link to a video example

Now realise that the surface is a solid being hit with something of immense energy. It will make a lot of the ground molten because of the energy, and act like the liquid example but will cool back to a solid in the process, so what you see is a slowing version of a droplet landing in a liquid, but eventually halting mid-formation because it's reforming as a solid.

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