Have you tried removing the vehicle and checking to see if the artifacts still exist?
I also think you need to re-think the craters. They look more like circles placed on the terrain. Craters really don't work like that.

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All the Woes of a World by Jonathan Icknield aka The Bryster

And in my final hours - I would cling rather to the tattooed hand of kindness - than the unblemished hand of hate...