Interest Check: The Manhattan Archipelago

[GrayOldFart]

I only have a moment, but here's the gist: natural disaster, such as earthquake and continental shift, causes Manhattan (and the surrounding area) to not only drop in altitude but suffer increased sea level. Most of Manhattan permanently drops 30 or 40 feet; most buildings to survive the disaster see their lower floors permanently under water, creating an archipelago of skyscrapers.

The story possibilities abound.

Gotta go.