How Sweden's arctic 'millipede town' Kiruna is slowly moving
http://edition.cnn.com/style/article/sweden-kiruna-relocation/index.html
I've heard some cases that residents in a town have to move due to natural phenomenon.
For example, Centralia in the state of Pennsylva became ghost town, because of coal mine fire, which has been burning even now.
Almost all of such cases have happened in countryside.
But, when it comes to megalopolis, it would be serious and it will be impossible to move all the buildings to alternative place.