think it's different geology - if you go to Google earth and look at tourist snapshots around there you can see that the light area to the north is significantly higher than the area with most of the buildings - looks as if it dips northwards and there is a major scarp running east - west
What astonished me is some bloody great warehouse type constructions and no sign of a herd of trucks or loading bays or a decent connecting road - a lot looks as if it was built and the rubbish left lying around and no-one there