A charitable take on Tokyo's landfill projects would have them simply extending the city's alluvial plains into Tokyo Bay. Given another millennium or two, natural siltation might end up doing the same thing.
By comparison, it's hard to think of any natural phenomenon that would result in the emergence of a trampoline-flat, 5-sq.-km plateau, filling the stretch of sea between what used to be two separate islands.
Welcome to the Cotai Strip, in the Special Administrative Region of Macau.